Built from 1969 until 1972, this building was the tallest in France, from the moment it was built up to the year 2011. Tour Montparnasse may not be much to look at from the outside. After all, it shares the skyline with the Eiffel Tower and is in the same city as architectural gems like the Louvre, Notre-Dame, Sacre Coeur and the Panthéon. And the SNCF train station in its foundation doesn't have much to admire, either.
It's not until you get to the 56th observation floor that visiting Tour Montparnasse becomes entirely worth it. The view from the Eiffel Tower is wonderful, sure – but the view from Tour Montparnasse has the Eiffel Tower in it! And on a nice day, the rooftop terrace on top of all 59 floors has a 360-degree view of Paris that is nothing short of breathtaking.
Tour Montparnasse is at 33 Avenue du Maine in the 15th arrondissement and can be reached by the Métro via lines 4, 6, 12 and 13. Once you exit the station, just look up!