Ritigala

There's an ancient ruin set in the middle of nowhere that you can explore.  It's called Ritigala.

You have to walk across fallen boulders and streams and stuff just to get to the main site, and even then, a lot of the stuff is off the main path deep in the jungle.  Not wanting to navigate through the bush alone, I just sort of stayed on the main path, but it is possible to go off trail and just look at all the fallen rocks.

It's hard to get to...no public transportation goes there, so you have to hire someone to take you down a very bad dirt road (which had lots of butterflies pooling around waterholes while I was there).

Here's my explorations of the park itself:

I sidebarred at one point and went climbing around in a stream.  It was better than the ruins themselves, actually.  As you can see from the pictures below.

The jungle from underwater.

And that was my short adventure at Ritigala.