The Anhangabaú Valley follows the course of the stream of the same name, bordering the western side of the hill where the city of São Paulo was founded. The stream was channeled in the late 19th century. In the following decades, the Valley was the subject of various architectural projects. The initial ones aimed to create a tree-filled park to shape the landscape and complement the esplanade of the São Paulo Municipal Theater. By the mid-20th century, however, the park had been replaced by new avenues and tunnels. It was not until the 1980s that the square project was implemented, creating an additional roadway level, as seen today.