The best sightseeing in Cayo would be at the Mayan ruins like the Xunantunich. I would also include the Mountain Pine Ridge area, which is a nature reserve that has pine trees. It is home to several animals, including jaguars, and it is part of the Elijio Panti National Park, where you will find different medicinal plants. Elijio Panti was one of the largely known Mayan Shamans (indigenous healer) in the area so this is a landmark and a legacy coming from him.
There are many other sightseeing sites in the Mountain Pine Ridge such as the 1000-foot waterfalls, the Rio on Pools, the Rio Frio Cave, the Caracol Maya temple, and different streams and campsites. The Rio Frio Cave is a dry cave, which is big enough for people to go into and which has two exits. There is a small stream going into the cave as well. The Rio Frio is highly popular to tourists. It is one of my favorite caves but other than what I have mentioned, there is not really a lot to see in the Rio Frio. There are some caves where you need a canoe in order to get in or you have to go tubing. The Rio Frio is a dry cave so you could just enter and get some impressive photographs of the insides of the cave and that’s about it. You can also go river and cave tubing at Caves Branch in the Cayo area.
Several resorts along the Macal River and the Mopan River also offer river tubing. Canoeing into the cave is another popular activity in Caves Branch. There are guided tours that take you inside the wet caves on a canoe. You need a flashlight to do this because it is very dark inside these caves.
The Intelco Hill in Belmopan City is another good spot for sightseeing. It is a overlooking the entire city of Belmopan and beyond. It is very nice to go there at night.
(Canoeing down the Machal River, Cayo, Belize, pictured.)