35 Rue du Chevalier de la Barre, 75018 Paris France
Along with the Eiffel Tower and Arc de Triomphe, Sacré-Cœur (Sacred Heart in English) is one of the most recognizable symbols of Paris and one of the most frequently visited sights by tourists.
Located in Montmartre, it is an active basilica. You can visit the basilica inside, even when the service is in process. If you would like to go all the way up, you will need to climb some 300 steps. If you don't feel like climbing the stairs, consider using Montmartre Funicular: it costs one metro ticket one way.