Krýsuvík, Grindavík 241, 5855500
Not too far from the centre of Hafnarfjörður rest the remarkable solfatara fields of Krýsuvík, where you’ll discover an expanse of steaming volcanic vents and boiling hot springs, framed dramatically by a range of multi-coloured hills. A well-maintained boardwalk winds through the bubbling and hissing geothermal area, with informative signage explaining all the important geological facts. The massive solfatara steaming away on the hilltop is a tempting attraction, even for those with tired legs, and the spectacular view of the surrounding area is well worth the extra legwork. As a short side-trip, you can also explore the coastline, where you’ll discover the stunning cliffs of Krýsuvíkurbjarg—an area renowned for its rich birdlife. Beside the mud pools and sulphur deposits, you'll find wildly colourful crater lakes. The Grænavatn, Gestsstaðavatn, and Augun lakes are old explosion craters formed by volcanic eruptions. Grænavatn Lake, 46 meters (150 feet) at tis deepest, glows with a deep green hue and is coloured so because of the presence of thermal algae and crystals that absorb the sun's rays. Gestsstaðavatn Lake draws its name from Gestsstaðir, a nearby farm, abandoned during the Middle Ages. On either side of the main road are two small adjacent lakes, called Augun (the eyes). Just a few minutes' drive from the surreal landscape of the geothermal area sit the stunning Krýsuvíkurberg Cliffs. Here, thousands of seabirds nest in the rugged hillside beside the crashing surf of the Atlantic Ocean. For a peaceful jaunt, hike along the trail to the edge of the cliffs where it's possible to spot kittiwakes, guillemots, razorbills, and other birds as they dive into the sea to feed or frolic with their flock. Contact the Hafnarfjörður Tourist Information Centre for a detailed map of the Krýsuvík area, including hiking and walking routes and information on local history, geology, folklore and attractions. Hafnarfjörður is located about 18 km from the city centre of Reykjavík.