South Iceland: See
Seljalandsfoss is one of South Iceland's many falls, falling off a 60-m-high cliff. west of Skógar.
Fjaðrárgljúfur Canyon is one of Iceland's most popular canyons, located near Kirkjubæjarklaustur.
A Golden Circle tour generally includes – at a minimum – Geysir, Gullfoss, and Þingvellir. Various companies offer day coach tours, or a better alternative is to rent a car for a day; this will let you see many more sights and often save money, especially if you have two or more people in your group. This also lets you vary the time you want at each attraction, linger at the geysers, or have a stop at Kerið.