We've all done it... you see an interesting pebble or stone on the beach and you take it home as a souvenir.
It might contain an interesting fossil or have unusual markings - or it might be that a youngster pockets it for their collection.
But it's a little known fact that it's illegal to take pebbles from the seaside.
The reminder comes as a poster has appeared on the beach at Amroth in Pembrokeshire warning that it's a criminal offence to take stones from British beaches.
The laminated sign doesn't reveal who displayed it, but reads: "The stones on this beach are part of Amroth's vital sea defences. Removal is a criminal offence. Offenders are liable to prosecution."
All of Wales' Blue Flag beaches in 2019
The offence falls under the Coastal Protection Act 1949, and offenders face a fine of up to £1,000 for leaving areas exposed to erosion.
The situation was highlighted in August last year when a holidaymaker was forced to drive hundreds of miles to return pebbles he "stole" from the beach after the local council threatened him with prosecution.
Beach pebble theft in Crackington Haven in Cornwall had become so common that St Gennys Parish Council put up several signs warning it was illegal.
But people have had mixed reactions to the sign appearing on the beach at Amroth.
Mark Woodward said on Facebook: "During the heyday of TV's Ground Force programme and Charlie Dimmock with her water features, in Dorset they had to sue people taking stones from the famous Chesil Beach as so many were being taken.
"People were going there with sacks to get them."
Dead sharks have been washing up on a west Wales beach:
But Ben Williams said it was difficult to stop sometimes.
He said: "When your three-year-old little girl wants to keep a pretty little pebble she found I can't say no.
"It's not what people take off the beaches that's the problem, it's what ends up on the beaches that people throw away."
A spokesman for Pembrokeshire County Council confirmed the poster was not one of theirs.
They said the council always put its logo on notices, and they would need to be bilingual if done officially.
