Study the Underground Urban Development potentials in promotion urban Safety Approaching Passive Defense

Nowadays, urban underground development, of all underground features, as fortune intact, for the spatial and functional needs, environmental, traffic issues, urban infrastructure development, upgrading urban sustainability. The important needs for urban infrastructures and high damage in crisis increase the large cities sensitivity. Underground space has positive potentials such as stability of temperature, hidden, high stability, can be accommodating humans and urban infrastructures in crisis to reduction the urban damages. This paper meanwhile, analysis the Iranian and word history in use of underground space, study the positive potentials with passive defense approach. Underground urban development with amends lack of urban underground space in big cities and traffic and environmental problems, can be used in passive defense goals. Underground space has basic and positive potentials in sustainability context. Underground development will be an excellent solution for problems and complementary contemporary urban requirements without destruction of culture heritage and damage of the environment. These potentials consist of temperature stability, sustainability in hard climate, stable in critical conditions and accidents, source of space; energy and etc. urban underground development approach can be used in solution of urban problems and upgrade their sustainability in big cities such as Tehran.