10 amazing underwater adventures

The best part of a destination may be what lies beneath its waters, whether you're diving ruins, palling around with sea life or peering out from a wacky-looking submersible. Grab your bags, masks, and fins — we're going deep for these 10 unique underwater adventures. | By Dara Continenza, SmarterTravel

More from SmarterTravel:

World's Most Unique Snorkeling Sites
World's Coolest Pools
Nine Secret Caribbean Attractions