Located in the central plain of the Attica Periphery, Athens is one of the world’s oldest cities and is the largest city in Greece. It is the fourth most populous capital city in the European Union. Prior to the Olympic Games of 2004, and up until current day, the metropolitan area has undergone tremendous development. Through a series of projects, Athens aims to address its traffic and environmental problems, pursue greater urban sustainability, and generally improve the quality of life. The greatest challenge it faces in this pursuit, is meeting mobility demands that do not threaten the built heritage that spans across Athens.