Hiking across a still-steaming crater is the iconic Big Island experience. You've just gotta do it! The rainforest home to two of the world's most active volcanoes and Hawaii's only World Heritage Site, Volcanoes National Park feels like a world of its own. There are miles of trails to choose from, but the marquee experience is crossing Kilauea Iki Crater. This moderate 4-mile (round-trip) hike starts with a half-hour amble through the rainforest high along the crater's rim (with multiple overlooks to the crater floor below); lush native plants and trilling birds fill the space, and the air is moist and fragrant. Eventually you reach a place where the path steeply descends for 400 feet to the abruptly barren, steaming crater floor. Follow the rocky cairns through the expansive, ethereal surroundings, passing multiple lava-lake steam vents. So otherworldly is this environment that you might feel as if you're tiptoeing around a lunar landscape. When you reach the opposite side, the trail ascends again, completing the loop. Full moon.

TIP: Upon completing the trail, make a small diversion to inspect the illuminated section of the Thurston Lava Tube, an old lava flow—now a giant cave—that goes on for miles. If you're feeling adventurous, bring a flashlight or headlamp to explore farther into the tube's unlit depths.

Hawaii Volcanoes National Park is about a 2.5 hour drive on Hwy. 11 from Kailua-Kona. For route details and information, check out the PDF brochure of the Kilauea Iki Trail.