Between Makkah and Madinah is the 20,000km2 Harrat Rahat lava-field with 644 scoria cones, 36 shield volcanoes and 24 domes. Between Madinah and the Great Nafud are the coalesced harrats Khaybar, Ithnayn and Kura with an area of 20,560km2 and 327 scoria cones, 46 basaltic shield volcanoes, 20 domes, 5 tuff cones, one basaltic stratovolcano (Jebel Qidr which looks like Mt. Fuji in Japan) and 39 massive and very long lava flows that we have named “whaleback flows” from their unusual appearance in the field. These the biggest and longest basalt flows in western Saudi Arabia and of course contain the biggest and most extensive lava-tubes.
Salt lake in two-km-wide Wahbah Crater.
The white silt layer gave the floor soft, rounded contours, whereas the walls and roof had shelves with sharp edges. When I looked into a small hole in the wall it was filled with the most beautiful small crystals, like an ice cave.