[Chinese and others on small bridge, with tower in background, Niagara Falls, N.Y.]

Stereographs are devices capable of building a three-dimensional​ image out of two photographs that have about two and a half inches difference between them so that it could imitate the two eyes’ real field of view. Combining these images into a single one with the help of stereoscope, a person can experience the illusion of the image’s depth. Stereoscope uses the same principle as in human binocular vision. Our eyes are separated by about two inches, so we see everything from two different angles. When the brain combined those views in a single picture, we get the spatial depth and dimension. Stereographs were extremely popular between 1850 and 1930 all around the world. Millions of stereographs were made during that time. There was a broad range of themes: landscape, travel, historical moments, nature disasters, architecture and many others. Nowadays, simply launch this collection full screen and put your mobile device in Google Cardboard Viewer.

Niagara Falls is a group of three waterfalls at the southern end of Niagara Gorge, spanning the border between the US state of New York and the Canadian province of Ontario. The largest of the three is Horseshoe Falls, also known as Canadian Falls, which straddles the international border between Canada and the United States. The smaller American Falls and Bridal Veil Falls lie entirely within the United States. Bridal Veil Falls are separated from Horseshoe Falls by Goat Island and from American Falls by Luna Island, with both islands situated in New York as well. Located on the Niagara River, which drains Lake Erie into Lake Ontario, the combined falls have the highest flow rate of any waterfall in North America that has a vertical drop of more than 50 meters (160 ft). Niagara Falls is famed both for its beauty and as a valuable source of hydroelectric power. In 1881, the Niagara River's first hydroelectric generating station was built. The water fell 86 feet (26 m) and generated direct current electricity, which ran the machinery of local mills and lit up some of the village streets. In 1893, Westinghouse Electric designed a system to generate alternating current. In 1896, giant underground conduits leading to turbines generating upwards of 100,000 horsepower (75 MW), we installed.

In the 19th century, a majority of Chinese immigrants were single men who worked for a while and returned home. At first, they were attracted to North America by the gold rush in California. A relatively large group of Chinese immigrated to the United States between the start of the California gold rush in 1849 and 1882, before federal law stopped their immigration. After the gold rush, Chinese immigrants worked as agricultural laborers, on railroad construction crews throughout the West, and in low-paying industrial jobs. Soon, many opened their own businesses such as restaurants, laundries, and other personal service concerns. With the onset of hard economic times in the 1870s, European immigrants and Americans began to compete for the jobs traditionally reserved for the Chinese. Such competition was accompanied by anti-Chinese sentiment, riots, and pressure, especially in California, for the exclusion of Chinese immigrants from the United States. The result was the Chinese Exclusion Act, passed by Congress in 1882. This Act virtually ended Chinese immigration for nearly a century.