Chichen Itza, Mexico
We decided to skip the organised tours for Chichen Itza and drove ourselves. We downloaded a guide to our phone and read about each of the ruins as we walked around at our own pace (a lot quicker than the organised tours)! Chichen Itza is hot! Scorching hot! So, it was preferable to us to be able to skip the bits we didn't find so interesting and focus on the bits we did.
There is a lot to see at Chichen Itza - it is a complex of Mayan ruins which includes El Castillo, pictured. Be sure to clap in front of the stairs and hear the returning echo claps... I'm not winding you up - try it!
The Great Ball Court is also pretty interesting and I'm sure it must be where J.K. Rowling got her idea for Quidditch!
Whilst you do have to queue for quite some time to get tickets to enter, Chichen Itza is one of the new seven wonders of the world not to miss!