The 14th of July is a national holiday in France - it's roughly equivalent to our 4th of July. BTW, the French don't call it "Bastille Day" they simply call it "le Quatorze Juillet" The holiday is characterised by several events:
1. A military parade down the Champs Elysees uncluding lots of soldiers, tanks, airplanes, and finishing with parachutists. This year's parade was marked by intermittent heavy rains which chased away lots of spectators - including me and my bicycle. However, I could watch the parade live on TV and wait as the jets flew past my windows.
2. Concerts - there were some enormous outdoor concerts - the biggest one in the place de la Bastille where I went to reconnoiter on my bike the day before. The musicians were rehearsing and doing sound checks when I went by. The round modern building in the background is the Opera Bastille announcing the programs for the upcoming season.
3. Bals des Pompiers (firemen's balls) - dances held in fire stations on the 13th and the 14th. There was one near my apartment with a long line of people waiting to get in. I didn't go - I think the average age was about 25. I could hear the music from my apartment though, it lasted until 4 AM.
4. Fireworks - start at 11 PM and best seen from the Eiffel Tower. I didn't go to see them live, just watched the sky and listened to the booms that I could hear from my place. I couldn't actually see the fireworks themselves, there was a building in the way, but the evening clouds were beautiful to look at.
I didn't get out much for the 14th - I am definitely a fair weather cyclist, and more of a reporter than participant. No matter, I enjoyed the rainy day, the evening sky, and staying home reading a good book. Besides, fireworks and dances and outdoor rock concerts are not much fun alone.