Swimming underneath waterfalls is a heavenly experience.
If you're into plants and trees a stroll through the Amazon rain Forest is an absolute must.
Hop off the boat, head straight into the heart of this massive dense green area and you'll find 10 to 20 different types of tree in a matter of minutes. In a normal (temperate) forest you'd only see three or four varieties of trees within this time.
Hangliding 
Walking (Amazon forest) 
