What city is represented by the city code CUN?

The city code CUN corresponds to Cancun, Mexico, which is a popular tourist destination known for its beautiful beaches, luxurious resorts, and vibrant nightlife. Airports around the world use three-letter city codes to streamline travel operations and communication. In this case, CUN is the designated airport code for Cancun International Airport, making it the correct answer in this context.

In terms of the other options, Puerto Vallarta has the city code PVR, Mexico City uses MEX for its main airport (Benito Juárez International Airport), and Houston's major airport has codes like IAH (George Bush Intercontinental Airport) and HOU (William P. Hobby Airport). Therefore, the association of CUN specifically with Cancun reinforces its accuracy as the correct answer.