From sustainable vacations to hopping a shuttle into space, we're looking at some very different future travel possibilities. Ecotourism expert, Gregory Miller, shares tangible tips on how to be an environmentally-conscious traveler and Rose Eveleth, host of "Flash Forward," describes what a journey to Mars might look like. Send us an email with your best travel stories and burning questions at [email protected] or find us on Twitter, Facebook, and Instagram @Expedia!