A four-year-old boy ended up in a gorilla exhibit at Cincinnati Zoo on Saturday, leading authorities to shoot the gorilla dead to protect the child.
While investigations are continuing into how the youngster breached the enclosure, we take a look at five other times people have got a little too close to the animals - with sometimes devastating consequences for them and the creatures involved.
1. Chicago's Brookfield Zoo - August 1996
A three-year-old boy climbs a 3ft (1m) railing and falls 18ft (5.5m) on to concrete in the primate exhibit at Chicago's Brookfield Zoo. He is picked up by a motherly eight-year-old gorilla, who carries him in her arms to a gate where zookeepers can get him. Keepers spray water at other gorillas in the exhibit to keep them away from the boy, who suffers only minor head injuries and scrapes.
2. Franklin Park Zoo, Boston - September 2003
An adolescent, 300lb (136kg) male gorilla named Little Joe escapes his enclosure at Franklin Park Zoo in Boston for a second time, injures a young woman and two-year-old child and roams around the zoo and city streets for nearly two hours before being sedated with tranquiliser darts and recaptured. The girl's grandmother says the gorilla threw the child to the ground.
3. Pittsburgh Zoo - November 2012
A two-year-old boy is mauled and dies after lunging from his mother's grasp and falling about 10ft (3m) from the top of a wooden railing into an exhibit of African painted dogs at Pittsburgh Zoo. He bounces off a net meant to catch falling debris and rubbish, then plunges into the enclosure. Some of the attacking dogs are called or drawn away, but police shoot one that is particularly aggressive. The boy's family sues the zoo but does not disclose details of the resulting settlement.
4. Little Rock Zoo, Arkansas - October 2014
A three-year-old boy goes over a railing, falls about 15ft (4.6m) into a jaguar exhibit at Little Rock Zoo in Arkansas and is bitten by two of the big cats on the neck and foot. The child's father throws objects at the jaguars, and employees use fire extinguishers to further deter them until a worker with a ladder pulls the boy to safety. He is critically hurt but survives.
5. Cleveland Zoo - April 2015
A two-year-old boy falls about 10ft (3m) into a cheetah exhibit at Cleveland Zoo after his mother dangles him over a railing. The cheetahs do mot approach, and his parents jump in and pull the boy to safety. He is treated for bruises.