Paris

Before the movie:
Paris is the capital city of France and located in Europe. This is one of the major cities that were attacked by the opposing alien force.

Battle: Los Angeles
A homemade video is shown during the movie where two children are seen pointing towards the alien command center for Paris. During that video, a scientist is explaining why the aliens are invading Earth. He says that the invaders are interested in the planet's water reserves. They will also use the sewer system to funnel their "fuel" back to their ships.