Hydra is a municipality in the wilaya of Algiers in Algeria, located on the heights of the city of Algiers at 210 m above sea level. Swanky and essentially residential, it houses the headquarters of around thirty embassies. Connected to Algiers city center by trolley bus from the early 1940s to the late 1950s, the center of Hydra today served directly by two lines? ETUSA 31 and 88. In addition, a bus station belonging to the municipality is a few tens of meters from the center of Bir Mourad Raïs, it is served in particular by lines 33 and 34 which pass through the Voirol column.