We started Day 4 with a hike to Hengifoss, one of Iceland’s tallest waterfalls. The trail to the falls was about 2.5 km each way, a moderately challenging hike that took us through breathtaking scenery, including views of another charming waterfall, Litlanesfoss, along the way. Hengifoss itself was mesmerizing, with its red-and-black layered rock formations telling a story of ancient volcanic eruptions. The effort to reach it made the sight even more rewarding, and we took our time soaking in the grandeur of the cascading water before heading back to the car.