A location everyone should try to visit once in life. The Baths in Virgin Gorda which is in the British Virgin Islands. It's about a 20-minute hike down some earthen steps to reach the water. There are a couple of beach areas with the largest called 'Devils Cove'. To gain access there is a direct trail and also an alternate trail through some caves formed from giant rounded boulders. Fantastic snorkeling although there can often be some significant surf.
I have a high-res version of one of these on my desktop computer and it really helps pick me up in the dark, cold New England winter.