If the conditions are right, you can see a natural blowhole in the reef behaving like Old Faithful, shooting salt water high into the air. It's most dramatic during big summer swells, which force large quantities of water through an ancient lava tube with great force. Stay on the paved walkways as rocks can be slippery and wave action unpredictable. Vendors hawk inexpensive souvenirs and other items in the parking lot. You may find good deals on shell jewelry, but ask for a certificate of authenticity to ensure it's a genuine Ni'ihau shell lei before paying the higher price that these intricate creations command.