The World Trade Center complex occupies 16 acres in Lower Manhattan and consists of five office towers numbered 1 through 4, a transportation hub, mall, and 9/11 Memorial and Museum. One World Trade Center, the tallest building at 104 stories, opened in 2014 as the lead building in the redevelopment of the site. The complex also includes 2 World Trade Center, 4 World Trade Center, and a memorial and museum dedicated to the victims of the 9/11 attacks.