Though the Palestinians don't have an army, rockets are regularly fired from Gaza into Israel. Israelis living in border towns are used to having to take shelter and adapting their lives to deal with the rockets.
In the years since Israel withdrew its troops in 2005, Gaza has seen several Israeli offensives. Israel says these were aimed at putting a stop to rocket fire.
In 2008, Israel sent soldiers into Gaza. An estimated 1,300 people, many of them civilians, were killed in Gaza before a ceasefire was declared; 13 Israeli soldiers also died.
In 2012, at least 167 Palestinians and six Israelis were killed during an Israeli operation. After eight days a ceasefire was declared with both sides promising to stop attacks.
Most recently in July 2014, Palestinian authorities said over 200 people were killed by Israeli air strikes and many more injured. Israel says more than 1,100 rockets were fired from Gaza, seriously injuring at least four Israelis, with one Israeli man killed.