 The tunnel linked the Sarajevo neighborhoods of Dobrinja and Butmir (that is why it is also called "Tunnel D-B"), allowing food, war supplies, and humanitarian aid to come into the city, and allowing people to get out.The tunnel became a major way of bypassing the international arms embargo and providing the city defenders with weaponry.Construction of the tunnel began in secret on 1 March 1993 under the codename "Objekt BD".