A visitor to an Anish Kapoor exhibition in Portugal was hospitalised after falling into one of the British artist's installations.
The visitor, an Italian man in his 60s, was injured after toppling into a 2.5m deep hole at the Serralves museum in Porto, Publico reports.
He was taken to hospital with back injuries, but has since been discharged.
The installation in question is Descent into Limbo – a seemingly bottomless hole in the centre of the floor in a large cube with a single door.
The hole is actually only 2.5m deep, but the sides have been painted with a dark black paint to give it the illusion of being a bottomless abyss.
Since there are no ropes or barriers around the work, visitors are made to sign a waiver acknowledging the safety risk, a museum spokesman said.
There were also warning signs and a gallery assistant in the room, the spokesman told the Times.
The installation has been closed since the incident to improve security, but should reopen in a few days.
Repairs will also be made to the work after it sustained a 'little bit' of damage when the man fell into it.
The work, originally created in 1992, is part of Kapoor's first major show in Portugal.
Previous visitors to Kapoor's exhibitions have questioned whether Descent into Limbo featured an actual hole or whether it was just a circle painted with black paint.