Question: UFC Fight Night: Namajunas vs. VanZant was held at a luxury resort casino and hotel opened on what date?
Sentence (from "UFC Fight Night: Namajunas vs. VanZant"): UFC Fight Night: Namajunas vs. VanZant (also known as UFC Fight Night 80) was a mixed martial arts event held on December 10, 2015, at The Chelsea at The Cosmopolitan in Las Vegas, Nevada.
Relevant evidence: Yes