A school in Dorset was evacuated after a pupil brought in a World War II shell to show to classmates.
The bomb squad were called to Queen Elizabeth's School in Wimborne at about 1630 BST after being alerted to a suspected bomb threat.
The device was taken into a playing field and detonated in a controlled explosion at about 1730 BST.
Police said the incident was now concluded and the school would be open as usual on Monday.
'Misguided youngster'
The mixed comprehensive school teaches 1,450 pupils, and was full when police were alerted to the device.
Inspector Matt Butler, of Dorset Police, said the teacher called police at 1400 BST after putting the shell in the field.
"The teacher didn't like the look of it and put it out in the middle
of the field and called us.
"We called in the bomb squad who blew it up so there's a hole in the middle of the playing field now."
He added: "There was nothing malicious. It was just a misguided youngster who thought it would be an interesting thing to show and tell and they certainly had an interesting afternoon with the police and the bomb squad."