Constructed from the 1960s on in order to meet a growing demand for office space in Paris, this ultra-modernist high-rise district, located west of the city, has had a bumpy history. A few design decisions made early on (especially those relating to the size of the towers) were eventually realized to have been mistakes, the area’s vocation was questioned, and its development strategy changed a few times (is it a mixed-use area? an office-only district? as of 2012, the favored answer seems to be the former... again).
Well over 100,000 office workers come to La Défense every day and the district is definitely worth a visit if you count yourself as an aficionado of modern architecture. You can easily reach it on Line 1 of the metro.