La Paz Waterfall, hidden in the rainforest of Costa Rica- I've been here! I have a picture almost the same as this! It's in the La Paz Waterfall Gardens, so it's not all that hidden. There's nice easy paths right to it! And some pretty bridges too!
Isla Espiritu Santo in the Sea of Cortez. This place is near the top of my list for most beautiful and peaceful places I have been. Crystal clear water and sea life abounds. We saw hundreds of dolphins, manta rays, whales, sea lions and many fun fishes