The Victorian era is, technically, the era of the long reign of Queen Victoria of England, from 1837 to 1901. But that's not really the *Victorian Era* of design. The Victorian Era of design is a time from after the end of the Civil War in the United States until the end of World War I, which is roughly 1870 to 1919. from a design standpoint, it is strongly influenced by the Industrial Revolution.
In general, you can recognize Victorian Era design by it's excessive ornamentation. Whether you are looking at a house built in the Victorian Era, or furniture, or books, you will see a lot of scroll work, a lot of detail, to the point of being excessive to most people's eyes. The reason for all of this ornamentation was simple, industrial processes had made doing this much cheaper. Before the Industrial Revolution, all of that ornamentation had to be done by hand, and was wildly expensive. When it all became mass produced, it was cheap and easy to give a *luxury* look to things, and people did.
The modern era began in 1919, with the end of the Victorian Era. It has flowed through such genius as Frank Lloyd Wright, and continues with the buildings, and designs, that you see today.