The hill on which Sacre Coeur is built isn’t really the highest point in Paris, but most people think it is. To reach the basilica, you have to climb 270 steps from the site entrance. If you arrive by Metro and decide not to take advantage of one of its rare elevators, add another 90 steps for the spiral staircase from the train platform to the surface.
Or, for the price of a single Metro ticket, you can take the funicular, which gives you a quick, pleasant ride to the top of the hill.
If you enbiggen this photo and look closely at the right-hand side, you can see pedestrians climbing the 270 terraced steps. They are probably either escaped mental patients, or athletes prepping for the summer Olympics. Or both.