On the way to the airport, we took a quick gander at Cancun. Not the town (which is now usually referred to Centro and is quite old) but the strip of hotels which juts out into the Caribbean. At the beginning of the 1970s there was nothing there. Then the Mexican government decided that it would make a good tourist destination,, and they were right. It, and the 100kms of coast stretching southwards (ending in Tulum where we've just been) accounts for 50% of Mexico's tourist revenue.
But we didn't like it. Endless hotels with 30,000 rooms and zero atmosphere. A cross between Miami Beach and Benidorm. What's more, because of the rapid development, the sand is literally being washed away and they're having to spend millions of dollars to keep it there.