Puerto Princesa

Gliding through the eerie, cathedral-like chambers of the Puerto Princesa Underground River feels vaguely like descending into the earth's wet, dark subconscious-a labyrinthine waterway ranked alongside Machu Picchu and the Great Wall as a New7Wonder of Nature, but refreshingly free of selfie-stick gladiators. Located in serene Cabayugan, this subterranean marvel stretches nearly five miles beneath the limestone karsts, emptying straight into an electric-blue sea like some mythical leviathan's backdoor. Do yourself a favor-arrive early (think crack-of-dawn early), to beat the sunburned crowds and catch the morning mist rising dreamily from the river mouth. Book at least two weeks ahead, budget around 1,500 pesos ($30 USD) for the whole experience, and be sure to pack a flashlight, sturdy shoes, insect repellent, and a tolerance for bats-thousands of them, hanging nonchalantly overhead as you float beneath. Even if dark caves aren't usually your jam, this is worth it, if only to casually mention at the next tedious cocktail party that you've drifted through an underground river surrounded by prehistoric fossils while strategically dodging bat guano.

Nothing spices up a vacation like poking around caves old enough to make your grandparents look positively sprightly. The Tabon Caves, tucked away in the lush and sweaty embrace of Quezon, Palawan, are famously known as the "Cradle of Philippine Civilization"-a fancy way of saying you're wandering through someone else's prehistoric living room, complete with ancient bones and the whispers of early humanity gossiping about cave bears and dinner etiquette. By dawn's early light is your best bet (not only cooler, but also the perfect lighting for that Indiana Jones selfie you'll pretend you weren't planning), so set your alarm clocks and prepare to channel your inner spelunker. Especially if it's peak season, aim to arrange your visit at least a few weeks in advance and budget around 500 pesos for entry fees, guides, and transportation-chump change in exchange for the bragging rights alone. Pack sturdy shoes, a flashlight, water, and your wide-eyed wonder; leave your claustrophobia at home. Trust me, even if archaeological tourism isn't quite your Netflix binge, the Tabon Caves are an experience worth having-if only to later casually mention at dinner parties your deep insights into the dawn of Filipino civilization and your newfound solidarity with cave-dwelling ancestors.

Getting to Tubbataha Reefs Natural Park isn't exactly a walk in the park; imagine voluntarily signing up to spend days on a boat, miles from shore, in pursuit of fish-and not even the grilled variety. This UNESCO-listed treasure chest, floating defiantly in the remote reaches of the Philippines' Sulu Sea, is the marine world's answer to an exclusive underground club-rich, vibrant, and maddeningly limited in access. You'll have to commit early (book at least six months ahead for prime dive season between late March and mid-June), splash out around $2,000 USD for a liveaboard dive trip, and bravely embrace 5 a.m. wake-up calls (the marine life waits for no hungover diver). Pack sunscreen, seasickness tablets, and your own gear (or risk looking like an amateur renting from the limited onboard stock). It's undeniably hassle-ridden-yet once underwater and face-to-face with swirling barracuda vortexes, languid manta rays, or leisurely drifting turtles, you'll feel like Jacques Cousteau in a slightly soggy version of heaven. Plus, surviving aboard a tiny floating hotel in the middle of nowhere makes for far better dinner-party tales than the usual beach vacation-and a distinct advantage in world-traveler bragging rights.