As the sun sets, Israel’s normally bustling streets begin to empty. Israelis all over the country start heading to ceremonies for Yom HaZikaron, Israel’s memorial day for fallen soldiers and victims of terror. At 8 p.m., the siren rings out. At that moment, Israelis stop what they are doing, wherever they are, and stand at attention — even if they are on the highway, they stop their cars and stand outside for 60 seconds. That siren announces the beginning of a 24-hour period of mourning.