Canoes, caves and indigenous culture: Adventure awaits in Mexico's San Luis Potosi

SAN LUIS POTOSI, Mexico - Imagine if you took a giant bottle of Champagne, shook it up, popped the cork and let the bubbles rush all over your body. Now imagine you're 60 feet beneath the surface and strapped into scuba gear when it happens. That, in essence, is the riotous joy one experiences when floating above a geothermal spring.

I've discovered this while swimming past one of the six springs that feeds a little-known prehistoric lagoon in Mexico called Media Luna. Lost in its whirlpool of bubbles, I watch in awe as they tickle their way around my skin, rising to the surface and popping in the midday heat.

Swimming through