As fighting between Israel and Hamas escalates, we've heard a lot about Israel's "roof knocking" technique.
Israel Defense Forces fire a small mortar round at an intended target to warn people inside to get out immediately. Shortly after, the real bomb falls.
Video footage captures the roof knock in action, and the aftermath of the bombing.
Israel has dropped fliers and made phone calls to Palestinians warning them to clear out of intended targets. IDF says the homes being bombed in Gaza are used to hide weapons and militants.
Violence between Hamas and Israel is at its worst level in several years. No Israelis have died in the fighting; 172 Palestinians are reported dead.
Tensions are getting worse every day with Israel's Operation Protective Edge dropping more than 1,300 rounds on Gaza, and Hamas continuing to fire rockets into Israel. The IDF says Hamas has hit Israel with 12,800 rockets since 2001, an average of three per day.