If you travel to the north coast of the Dominican Republic, I suggest, hitting up 27 Charcos. Charcos meaning waterfalls. It is an amazing experience. You hike up a mountain with a tour guides. No tour is bigger than 10 people. Once, you get to the top, you make your way down via rope swing, sliding down limestone, or jumping into pools of water. It is one of my top 10 favorite experience with nature and probably top two in the Dominican. The first was horse back riding.
It says to just wear a bathing suit or Tevas or sneakers. I went for a one piece that would ensure that everything stayed where I wanted it to (in my bathing suit).
P.S. - I am sorry to have ever criticized the appearance of a Tevas in my entire life. That shit is comfortable.