Grand Erg Oriental small but ancient settlement of Ghadames at the Libyan frontier. Another and better road from Hassi Messaoud goes south, also crossing the grand erg where it passes a well called "Hassi Tartrat", before reaching the erg's far side. Further south lies the Ahaggar mountains. The cities of Wargla and Touggourt lie outside the western limits of the erg. Nearby, within the accepted boundaries of the "Grand Erg Oriental", the landscape is described as being "practically free from [sand] dunes" evidently due to strong, persistent winds. Petroleum and other hydrocarbons have been extracted in Algeria, from areas in and surrounding the
Grand Erg Oriental "Grand Erg Oriental". In addition to oil in Wargla and Hassi Messaoud (see above), other Algerian hydrocarbon sites include In Salah, a city (pop: 44,000) to the erg's southwest, yielding natural gas, and also El Adeb Larache, Edjelé, Tingentourine, and Zarzaïtine (south of the erg, close to Libya). One of Algeria's largest field of natural gas is near Ghardaïa, west of Touggourt. Gas pipelines have been constructed north to the Mediterranean port of Bourgie, and later northeast through Tunisia. Along the north rim of the "Grand Erg Oriental", both the physical ecology and the human culture surviving there since ancient