Tikal National Park, which was once home to over 150,000 Mayans, is a UNESCO world Heritage Site located in NE Guatemala, in the department of Peten. If you make it to Tikal at some point, I would recommend staying a night in the park so you can do a sunrise tour.
Not only is watching the sunrise from the top of a Mayan temple worth getting up at 4am and climbing 198 steps, but the sounds of the jungle waking up in the morning is pretty incredible too: howler monkeys and 380 species of birds can make quite a racket…in a good way.
However, on a sunrise tour you’ll see a few highlights, but miss most of the site, so we also spent several mid-day hours exploring and wandering on our own. This was the perfect combination of organized tour and self-guided exploration.
Seems ruins and monkeys go together, so you’ll probably also want to hang out and watch the monkeys.