Varosha, Cyprus, has what may be the greatest example of abandoned hotels in the world.
After their little civil war, in the '70s the "Green Line" between Greek and Turkish areas was drawn down the middle of the island based on where forces of each side happened to be at the time.
A newly constructed luxury resort area belonging to Greeks ended up on the Turkish side of the line. Rather than bulldoze it, the Turks decided to leave the area abandoned on the expectation that this tourist area would be so valuable to the Greek side that they'd be able to trade it for some concessions.
30+ years later that never happened, but the area has remained fenced off, uninhabited, and unrazed.
It's a pretty interesting story, a full chapter in
The World Without Us talks about it since it provides a great real-world example of how urban areas decay in the sudden absence of humans.