This Instagram photo from a riot in Tahrir Square was snapped by Bobby Ghosh (@ghoshworld), an Editor-at-Large for TIME Magazine (@TIME). Bobby says it was "pure, blind luck" that he managed to capture this moment. He was caught in the middle of a protest when a tear-gas canister soared through the air towards him. Without thinking, he snapped a photo with his iPhone just as the canister landed at his feet. Later, when out of harm’s way, he discovered the photo and decided to share it to Instagram, where the TIME photo editors would first find it. “I knew it was a good image, but couldn’t be sure how good…when the folks in NYC told me they were going to run it in the magazine, I was quite surprised," Bobby says. "People seem to be responding to the human drama in the image, the Egyptians scattering in different directions as the tear-gas canister lands. Somehow, I seem to have captured this electric moment." To see more photos from Egypt's famous Tahriri Square, tap the location text above.