Ready to journey deep beneath the Earth’s surface to explore one of the longest lava tubes in Washington? From scrambling over boulders in the rugged Upper Cave to strolling through the eerie stillness of the Lower Cave, this underground adventure was unlike anything we’ve ever experienced. If you’re craving a family-friendly thrill that blends natural history, geology, and a touch of mystery, the Mt St Helens Ape Caves are a must-see.