When people hear the word Tokyo, they picture neon billboards, thirty-seven million people, and the busiest train stations on Earth. Yet this island in the middle of the Philippine Sea is officially part of Tokyo. Every car on the island wears a Tokyo license plate. This is Aogashima, an active double-caldera volcano rising 1,380 feet straight out of the deep blue ocean, two hundred and twenty miles south of the capital. Inside a massive outer ring of jagged volcanic cliffs sits a second, smaller green cone called Maruyama. Only about 160 people live inside the crater, making it the smallest municipality in Japan. There is one general store, one post office, and zero traffic lights. The only way in is a twenty-minute ride on a nine-seat commuter helicopter or a small ferry that can only dock when the ocean waves allow it. Living inside an active volcano comes with a perk. Around the inner crater, natural geothermal steam vents called Hingya hiss out of the earth. Locals do not need gas stoves to cook lunch at the park. They place sweet potatoes, eggs, and fresh fish inside wooden boxes built directly over the volcanic vents and steam them for free. They even use the volcanic heat to evaporate ocean water into prized mineral salt. At night, with zero city lights for two hundred miles, the sky above the crater turns into a solid ceiling of stars.