Each of the towers was designed by a different architect. The47-story Mandarin Oriental, designed by Kohn Pederson Fox, is a400-room hotel topped by approximately 227 luxury condominiums.Approximately 93% of the condominiums have been sold, generating$656 million in sales, according to Citycenter.

Last month, steel workers laid the final piece of steel for theAria Resort & Casino, the anchor property with 4,000 rooms intwo 61-story towers designed by Pelli Clarke Pelli. In June,workers placed the last piece of structural steel for the Vdara, a57-story, 1,500-unit condo hotel designed by Rafael Vinoly.

The two towers still on the rise are the Harmon Hotel, Spa &Residences, a 49-story designed by Foster & Partners with 207condominiums above 400 hotel rooms, and Veer Towers, two 37-storytowers designed by Helmut Jahn that appear to lean in opposingdirections. The towers house 674 condominiums.