The wall is a series of sand and stone walls of two to three meters high; it extends along topographic high points (such as peaks and mountains) throughout the Sahrawi Territory. It is protected by bunkers, ditches, trenches, barbed wire, mines and electronic detection systems and defended by more than 160,000 Moroccan soldiers. Over every 5 kilometres of the wall, there is a military base of about 100 Moroccan soldiers. About four kilometres behind each major observation post, there is a mobile rapid intervention force (with armoured vehicles, tanks, etc.) A series of overlapping fixed and mobile radars, with a range of 60 to 80 km, are placed along the wall. According to some sources, Morocco spends $ 2 million daily to maintain the wall..