Visitors to Hadrian's Wall are being urged to help take care of the ancient monument.
National Trails, which manages the 84-mile walking route that follows the Roman wall, has raised concerns about damage to the World Heritage Site.
The organisation said too many people were walking on the wall while some had broken off masonry as souvenirs.
However, it stressed that the majority of visitors treated the wall with respect.
David McGlade, Hadrian's Wall Path National Trial Manager, said people should enjoy their visit, but also help look after the site.
He said: "Unfortunately there are still people who want to walk on top of the wall.
"They're probably thinking in their own mind that they are walking in the steps of the Romans, but we would prefer they didn't do that."
A few people have been seen breaking pieces of the wall, he added.
"That's really strictly against the law. It's Hadrian's Wall - it's a scheduled ancient monument and that is a reportable offence."
The wall was built in 122 AD on the orders of the Roman emperor Hadrian, and connects Wallsend, near Newcastle, with Bowness-on-Solway on the west coast.