Tucked away on a hill in the heart of France’s capital lies a neighborhood that feels like a village within a city. With cobbled streets, crimson cafés, and painters on every corner, Montmartre is Paris’s bohemian soul—crowned by a shining white basilica that watches over the city like a guardian angel.

High in California’s Eastern Sierra, just off Highway 395, lies a body of water so strange it might as well be from another planet. Mono Lake is a landlocked saltwater basin that’s more than 760,000 years old — one of the oldest lakes in North America. But what truly makes it a hidden wonder is what rises from its waters: towering, ghostly formations called tufa.