Significance: Encouraged by the good results being obtained by the Metropolitan Sewerage System, the Massachusetts legislature of 1893 authorized the State Board of Health to make investigations for a metropoli More
Significance: This structure is part of the Green Butte Copper Company mining district. Constructed of wood, this wood frame structure is located ten feet north of the bunkhouse in the lower camp. Survey numb More
Significance: The saw shed is one of the original buildings in the Newlands Project Facility Yard. It was built to house the power saw in the lumber yard. Survey number: HAER NV-6-J Building/structure dates: More
Significance: Part of the Green Butte Copper Company mining operation. This rectangular, 10' x 14' structure is made of corrugated metal and has 'Seattle Hardware Co., Green Butte Mining' stenciled on its wall More
Significance: Part of the Green Butte Copper Company mining operation. This wood frame structure has a platform roof with cable tram bull wheel. Survey number: HAER AK-9-F Building/structure dates: 1924 Init More
Significance: The 12' x 12', wood frame stairway is attached to the bunkhouse that was used by miners employed at the Green Butte Copper Company. Survey number: HAER AK-9-I Building/structure dates: 1925 Init More
Significance: The 12' x 12', wood frame stairway is attached to the bunkhouse that was used by miners employed at the Green Butte Copper Company. Survey number: HAER AK-9-I Building/structure dates: 1925 Init More
Significance: The 12' x 12', wood frame stairway is attached to the bunkhouse that was used by miners employed at the Green Butte Copper Company. Survey number: HAER AK-9-I Building/structure dates: 1925 Init More
Significance: The Canton Viaduct is a granite structure 615 feet in length, 22 feet in width, and 70 feet above the surface of the Neponset River's East Branch. The viaduct was the principal structure on the B More
Significance: The Canton Viaduct is a granite structure 615 feet in length, 22 feet in width, and 70 feet above the surface of the Neponset River's East Branch. The viaduct was the principal structure on the B More
Significance: The Canton Viaduct is a granite structure 615 feet in length, 22 feet in width, and 70 feet above the surface of the Neponset River's East Branch. The viaduct was the principal structure on the B More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: This structure is the only surviving suspension bridge in the American West dating to the mid 19th century. When reconstructed over Lake Oroville, it was "strengthened" with pile supports under t More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: Throughout its more than eighty year history, the General Dynamics Corporation/Quincy-Fore River Shipyard was one of the leading private shipyards in the United States. Producing both military an More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: This building houses seven vertical cross-compound condensing steam engines. These blowing engines originally produced wind for the Clairton Works blast furnaces. In ca. 1961, two furnaces (#6 a More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More
Significance: The Smith Avenue High Bridge, a nineteenth century wrought iron Warren deck truss, is the longest and highest roadway truss bridge in Minnesota. It was designed by Keystone Bridge Co. of Pittsbur More