How'd you like to buy the absence of a ton of invisible gas on your next trip? Introducing "carbon offsets."

At this 10-unit retreat bordered on three sides by the Stuarts, Browns and Cacao rivers, everything is designed to have as little impact as possible on the environment.

The Inn by the Sea offers room service, honeymoon packages, DVDs and, in its restaurant, classic dry martinis.

Green hotel specialists have identified several criteria that eco-minded hotel shoppers should look for.

All of the most prominent online travel agencies -- Expedia, Orbitz and Travelocity -- offer a convenient way to voluntarily pay to offset CO 2 emissions caused by a trip.