Metro Tower is a skyscraper and the tallest building in New York City, which was ambushed during the Krang's invasion on Earth.
History
After the Krang captured Raphael and turned him into a Krang Zombie, will his help they were able to ascend Metro Tower in order to retrieve the Technodrome as well as the Krang's Titans.
Once Casey was able to ascend the skyscraper and steal the Mystic Key, Leonardo orders him to pull it once him and Krang One are inside the Prison Dimension, closing the portal, destroying the Technodrome, and trapping both Leo and Krang One in the Prison Dimension. Leo throws one of his katana into the portal and stabs Krang One's Titan with it, teleporting them both into the Prison Dimension. Casey tearfully does as instructed, trapping them both inside and destroying the Technodrome.
After Michelangelo, Raphael, and Donatello rescue Leonardo from the Prison Dimension and defeat the Krang, New York City begins rebuilding from the chaos that ensued during the invasion, rebuilding Metro Tower.