First promoted as a residential area in the early 19th century, Union Square and its surroundings became the first theater district of New York City (The Rialto) after the 1850s. The development of public transportation in the early 20th century has reshaped the neighborhood for the purpose of retail stores and businesses, and several notable buildings are still witnessing that prosperous age. The square itself has an extremely rich history in terms of gathering point for social and political activism, and many memorials & monuments testify their use for the memory and the commemoration in the park.