Question: In what state did Olivia Newton-John perform Summer Nights? 
Related documents: [0]  [DOC] Summer Nights is the debut residency show by Australian recording artist, Olivia Newton-John. The show takes place in the Donny & Marie Showroom, at the Flamingo Las Vegas. The show began April 2014 and is slated to complete September 2015. [END] 
[1]  [DOC] Flamingo Las Vegas (formerly The Fabulous Flamingo and Flamingo Hilton Las Vegas) is a hotel and casino located on the Las Vegas Strip in Paradise, Nevada. It is owned and operated by Caesars Entertainment Corporation. [END] 
Answer: 
Nevada
Nevada