After a month's journey through wastes so harsh that even some of the camels died, on 2 February 1932 Philby arrived at a patch of ground about a half a square kilometre in size, littered with chunks of white sandstone, black glass, and chunks of iron meteorite.
Philby identified two large circular depressions partially filled with sand, and three other features that he identified as possible "submerged craters".
Philby had heard of Bedouin legends of an area called Al Hadida ("place of iron" in Arabic) with ruins of ancient habitations, and also an area where a piece of iron the size of a camel had been found, and so organized an expedition to visit the site.
Courtesy Jeff Wynn Hamann, C., Hecht, L., Ebert, M., Wirth, R., Chemical projectile-target interaction and liquid immischibility in impact glass from the Wabar Craters, Saudi Arabia.
and See, T H., Dissemination and fractionation of projectile material in impact melts from the Wabar crater, Saudi Arabia (abstract).
The largest crater is 330 feet (100 m) in diameter, 40 feet (12 m) deep, partially filled with sand, and thought to be an explosion crater (formed from an explosion on impact).
A crater located 0.6 mile (1 km) northwest is about half the size of the main crater and is thought to be two partially superimposed craters.