Southeast of Húsafell, the absolutely incredible Kaldidalur valley skirts the edge of a series of glaciers, offering incredible views of the Langjökull ice cap (the second largest glacier in Iceland) and, in clear weather, Eiríksjökull, Okjökull and Þórisjökull. The Kaldidalur Corridor, also simply known as unsurfaced Rte 550, is slow but dramatic going (mountain ice, barren rock), and often fogged in in summer. It links south to the Golden Circle, offering the option to create an extended loop from Reykjavík. Access to Rte 550 is limited to sanctioned vehicles – ask your rental outfit before setting off.
The primary way to see the Kaldidalur Corridor is with your own wheels or on the Reykjavík Excursions bus, but tours are available on Langjökull and of the glacier's new ice cave, departing from Reykjavík or Húsafell. Do not attempt to drive up onto the glacier yourself.