The Galápagos Islands, off the coast of Ecuador, are one of the world's most famous destinations for outdoor enthusiasts, thanks to their melange of unique wildlife and otherworldly landscapes. The chain of 19 islands offers many once-in-a-lifetime activities, from hiking on volcanos to relaxing in the saline Darwin Lake with nearby tortoises and iguanas. Cruising is one of the best ways to reach the islands; for an eco-friendly option (think solar power technology and reduced plastic waste), book with Quasar Expeditions.
The Half Dome trail through Yosemite may be one of the most intense hikes you'll ever take, stretching for 16 miles and ascending more than 5,500 feet. The final 400 feet are the trickiest—hikers must climb up the steep slope with two steel cables as their only support—but the breathtaking views from the top make the effort (and terror) worth it. Afterwards, stay at The Ahwahnee, one of the most beautiful national park hotels in the country.
