Notre Dame Cathederal, Paris

Notre Dame Cathederal in Paris. Not really much needs to be said. Just zoom in one more click and look at those flying buttresses. If you must, here's the wikipedia article and here's their webcam.

Basilica Notre Dame, Montreal

Basilica Notre Dame in Montreal. Here's the wikipedia article. On its completion in 1830, the church was the largest in North America.

Ile Notre Dame, Montreal

Ile Notre Dame in the middle of the Saint Lawrence River in Montreal is the home of the Canadian Grand Prix. Zoom in a couple of more clicks and you can clearly make out the track.