1. Oregon. This northwestern haven for all things green is possibly the most eco-conscious state in the nation. With more than 300 miles of stunning coastline preserved as public land, families can visit pristine beaches, bike in two-wheel-friendly cities like Portland and Eugene, and raft on wild and scenic rivers. You can also explore high deserts, farm and wine country and the Columbia River Gorge, all within one grand holiday. Details: 800-547-7842; www.traveloregon.com.
2. Borneo. Visit this exotic island to see the world's largest flower and to discover sparsely populated beaches, caves, lush jungles and an expansive list of endemic plant species. Trek through the virgin jungle to Mount Kinabalu and explore the Kinabatangang River region. Be on the lookout for wild boars, orangutans, macaques, elephants, kingfishers and proboscis monkeys. Stay in award-winning eco-lodges featuring solar power, the harvest of rainwater and wildlife rehabilitation efforts. Details: www.visitborneo.org.
3. Sundance Resort, Sundance, Utah. Robert Redford is the eco-minded force behind this mountain resort that provides a high-altitude lesson in good fun and environmental stewardship. Join guides for a snowshoe trek under the night sky in search of owls. By day, enjoy skiing, hiking, horseback riding, art projects and music. The resort operates on wind power, recycles its own glass and offers organic linens, amenities and vegetables. Carpoolers receive $5 off lift tickets for their energy-saving efforts. Details: 877-831-6224; www.sundanceresort.com.
4. St. Croix, U.S. Virgin Islands. Follow the underwater trail and enjoy one of the few fully protected marine areas in the world. Run by the National Park Service, the 176-acre island and surrounding coral reef ecosystem form Buck Island Reef National Monument, a nature lover's paradise. Intensely colored fish and coral thrive in a turquoise sea, providing a visual treat for both novice and experienced snorkelers and divers. The preserve can be reached via half- and full-day charters. Details: 340-773-1460; www.nps.gov/buis/index.htm.
5. Belize. Explore Mayan sites deep in the jungle and scope out brightly colored birds and exotic flora and fauna in this diverse country, enriched by 87 distinct ecosystems. Divers and snorkelers choose from hundreds of underwater wonders as they explore the world's second-longest barrier reef. Go cave tubing, zip-lining and beach walking in a country where locals are eager to share their vibrant, nature-loving traditions. Details: www.travelbelize.org.