Satellite imagery shows a steady increase in the number of buildings destroyed in middle and southern Gaza. Most damage appeared after Oct. 13, when Israel's military urged evacuation from the north.

It's not unusual for countries to restrict satellite images of sensitive locations. But in the case of Israel, a U.S. law seeks to protect an entire — and separate — country.

The Israeli military appears to have encircled Gaza City, but so far, it's made only limited forays into the densest urban areas.

Lillian Kay Petersen, 17, has won the Regeneron Science Talent Search, a top science and math competition for high school seniors. Her winning project: a tool to predict crop harvests.