23. Diamond Head State Monument – Honolulu, Hawaii
There are many American destinations here that have hiking involved, but you may want to put this one at the top of your bucket list. You get to hike up a 300,000-year-old volcanic crater, placing you at 560 feet above sea level (via Fodors). The view is essential to American history, as the military once used the lookout to protect the island from attacks. Along the route, there are abandoned bunkers still lying around that offer a good platform for whale watching or just watching the sunrise if you get up there early enough (via Fodors).