The Astor Place Cube,formally, named Alamo

The New York City parks department lists 843 permanent artworks on its sites, including monuments, fountains, mosaics and other styles. Astor Place’s cube   named  "Alamo"  was the first permanent contemporary outdoor sculpture installed in New York City. It was created by American  artist Tony Rosenthal, best known for his monumental public art  sculptures. His art dealer Sam Kootz, who also represented Pablo Picasso, not only  convinced  to use the nickname "Tony" instead of his real name Bernard. Koots also   recommended  the artist name to concentrate on creating abstract geometric sculptures.
  Alamo was originally created  for a citywide exhibit, put on by the New York City Parks Department, called “Sculpture in Environment.” The sculpture's name, Alamo was selected by the artist's wife because its scale and mass reminded her of the Alamo Mission.

Spanish Mission

This Spanish mission complex, originally known as Misión San Antonio de Valero, was the first of six San Antonio missions founded by Catholic missionaries along the San Antonio River in the early 1700s. Spanish soldiers used the mission church as a fort during Mexico’s fight for independence from Spain.

In the same year, 1967,  Rosental also created cube in  Detroit.
 These two cubes were the first ones but not the last ones created by the sculptor.  A year later in 1968 a cube in   Ann Harbor, Michigan was created.  In 1972  similar cube appeared in New London, Connecticut.

Cube in Michigan

The cube has been the subject of numerous pranks and hoaxes, from being covered in yarn to being converted to a Rubik’s cube. In 2013, a fake documentary claimed a 37-year-old writer named Dave lived inside the sculpture.  There was even a legend that kissing the cube ensured a relationship would last forever.

Cube in Detroit

 The cube was  made out of weathering steel ( trade name Cor-ten). Weathering steel is a high strength low alloy steel that was originally developed by United States Steel in the 1930s to resist corrosion and abrasion.
The Cube was removed from its spot in 2014 in order to facilitate the renovation of the public space, including the addition of seating and more pedestrian plazas. The cube returned to its place in 2016.