A teenager was arrested on Sunday after allegedly throwing a six-year-old boy from a tenth-floor viewing platform of London's Tate Modern gallery,
police said.
The boy was airlifted to hospital and is in a critical condition, while the 17-year-old male suspect is being held on suspicion of attempted murder.
The Tate Modern, a leading contemporary art museum on the banks of the River Thames, was initially locked down but visitors were later allowed to leave.