As a lawyer, Robert Highsmith plunges into legislative, administrative and regulatory law, but when he's off duty, he goes to even greater depths.

The Holland & Knight partner has a passion: underwater cave diving. He first got into scuba diving in college, then moved on to highly technical cave dives. The lure for Highsmith, in large part, is because of his interest in exploring hitherto-unknown or unidentified sites and shipwrecks.

In addition to extra training and certification, cave divers carry complex gear, and more of it. One reason for the extra tanks and breathing devices is that cave divers are usually farther away from the surface than a standard scuba diver.