During conservation work at Jerusalem’s Damascus Gate, built in the 1500s by Suleiman the Magnificent, workers discovered a 100-year old Turkish hand grenade in the core of the wall.
Israeli antiquities experts believe that someone stashed the grenade in the middle of the wall through some broken stone during the last years of the Ottoman Empire.
But, what if there were another explanation? What if someone from our near future slipped back in time to visit the Grand Sultan during the height of Ottoman rule, making a pit stop in the Empire during World War I to pick up supplies and weapons?
Perhaps the grenade ended up in the wall as it was being built. A good writer could really build a story around that.