ieExplains: What are Israel's Iron Dome and Arrow missile defences?

Israel's Iron Dome system intercepting rockets. 

Israel’s multilayered air defence system appears to have passed another test after fending off Iran’s latest missile barrage.

In Tuesday’s night’s strike, Iran fired over 180 missiles toward Israel. The attack set off air raid sirens across the country and sent residents scrambling for shelter, but caused only a handful of minor injuries and limited damage, in large part because many were intercepted or landed in open areas.