Why to go now: The sheer number of endemic species inhabiting the Galápagos Islands, an archipelago 620 miles off the coast of Ecuador, inspired Charles Darwin to formulate his evolutionary theories and write 'On the Origin of Species.' There are myriad species living on these actively volcanic islands found no place else on Earth, including marine iguanas and giant tortoises. More than 100,000 tourists visit the Galápagos annually, which has resulted in the introduction of invasive species like pigs (smuggled in by workers) and rats (stowed away on boats) and landed the destination on the World Heritage Site Danger List from 2007 to 2010. Environmentalists warn that the islands aren't yet in the clear. Tourism continues to rise 12% year over year with the infrastructure alone threatening to forever alter the once isolated islands.

How to get there: Vancouver-based BikeHike Adventures offers active travel with a minimal footprint. Their 10-day Galápagos Multi-Sport does away with cruise ships and motor vehicles, opting to explore the island by kayak, foot, and bike.