Mandalay Bay is a 43-story luxury resort and casino at the south end of the Las Vegas Strip in Paradise, Nevada. It is owned by Vici Properties and operated by MGM Resorts International. It was developed by Circus Circus Enterprises and completed at a cost of $950 million. It opened on March 2, 1999, on the former site of the Hacienda hotel-casino. MGM acquired Mandalay Bay in 2005, and Blackstone became a co-owner in 2020. Vici acquired MGM's ownership stake in 2022. Mandalay Bay has a tropical South Seas theme and covers . It includes a casino and 3,209 rooms. The 43-story tower includes a Four Seasons hotel, which has rooms on floors 35 through 39. It is managed separately from the Mandalay Bay hotel. In 1999, the Four Seasons became the first Las Vegas hotel to win the AAA Five Diamond Award. Several additions opened in 2003, including the Mandalay Bay Convention Center, and a second hotel tower, THEhotel at Mandalay Bay. It has 1,117 rooms, and was renamed Delano Las Vegas in 2014. A shopping mall, Mandalay Place, was also added in 2003. Other features include a House of Blues club, the Shark Reef aquatic attraction, and an events center known as Michelob Ultra Arena. The resort also has an 1,800-seat theater, which has hosted several Broadway shows, including Chicago (1999–2000), Mamma Mia! (2003–2009), and The Lion King (2009–2011). Since 2013, the theater has hosted Michael Jackson: One. In 2017, gunman Stephen Paddock opened fire from the hotel's 32nd floor, killing 60 people in attendance at an outdoor music festival nearby. It is the deadliest shooting by a lone gunman in U.S. history. History Mandalay Bay was built on the former site of the Hacienda hotel and casino at the southern end of the Las Vegas Strip. In 1995, Circus Circus Enterprises purchased the Hacienda for $80 million and an adjacent site, directly south, for $73 million. That June, plans were announced for a new resort project, tentatively known as Milennium, to replace the Hacienda. The Hacienda closed on December 1, 1996, and was demolished on New Year's Eve. Details about its replacement were unveiled on the same day; the tropical-themed resort, now known under the working title "Project Paradise", had an estimated budget of $800 million to $1 billion, with completion expected by the end of 1998. The target clientele would be higher-end compared to Circus' prior