El Charco Verde
This bizarre green lagoon, which looks like something out of a sci-fi thriller, is situated at the outer limits of Timanfaya National Park just uphill from El Golfo. It gets its radioactive hue from its sulfuric content and Ruppia maritima seagrass. It's forbidden to walk to the lake as it's within the reserve, but there's a viewpoint that's clearly marked at the turnoff to El Golfo where you can snap some excellent photos, especially at sunset. Wear grippy shoes and watch your step, as there are no guardrails around the viewpoint.