What is Hamas and why is it attacking Israel?

#OMG: Video shows Hamas militants attacking music festival in Israel

Video of Israeli bombing of hospital in Gaza

Israeli fighter jets launch series of violent airstrikes east of Gaza's Shujaiya neighborhood

Crows presage Israel's downfall after attacking country's flag

Sedena planes leave for Israel to return Mexicans, so their trajectory

Palestinian celebrates Hamas rocket fire into Israel and later releases a video of him crying in a hospital after a bomb

Kitten suffers eye and skin burns after Israeli fighter plane bombardment

Last message of Mexican woman kidnapped by Hamas in Israel

Plane with a banner that reads "U.S. supports Israel" and "Hamas is ISIS."

The father of Noa Argamani, a young woman kidnapped at a music festival by Hamas militants along with her boyfriend Avin