They used white spray paint to scrawl offensive graffiti onto a memorial, gravestones and the grass in Glasgow's Necropolis.
The anti-religious vandalism on the monument of Scottish reformer John Knox, is at the highest point of the cemetery overlooking the city.
And around a dozen gravestones surrounding the statue have also been defaced.
The cemetery lodge at the entrance to the Necropolis also has swastikas scrawled into the wooden doors.
The Evening Times alerted Glasgow City Council, which sent a team of workers to clean up the mess. It is not the first time the city landmark has been targeted – and there are now calls for more to be done to stop vandals.
Glasgow residents and tourists say they are appalled by the incidents.
Lesley Naughton, 52, from Craigend, said: "I think it is disgusting. There are people buried in there, so it is absolutely disrespectful for people to be vandalising or spray painting on the gravestones.
"It is such a nice place for the public to visit. We need to get the message out that it is not okay for people to act like this. I think there should be more patrols looking out for this sort of thing."
Keiran Kerr, 18, a student from the city, said visitors to Glasgow would remember the mess instead of the stunning cemetery.
He said: "It's mindless vandalism. I don't think there's any point of it. It's one of the things that people will remember.
"And the tourists will think about the graffiti over anything else. It's just thoughtless."
Bernadette Branney, 55, from Royston, said: "I just think it's disgraceful that people could do that, especially in a graveyard."
Paul Connelly, 43, who works in nearby Glasgow's Royal Infirmary, added: "It is always busy around here with tourists so it's painting a bad image of the city. Everyone enjoys the Necropolis so why spoil it?"
Around 50,000 people have been laid to rest at the 37-acre cemetery, which is behind Glasgow Cathedral, and 3500 tombs have been built there.
Some of the monuments, which were made for entrepreneurs, were created by renowned designers including Alexander 'Greek' Thomson and Charles Rennie Mackintosh.
In July 2011, the Evening Times told how Nazi symbols and racial abuse was spray painted on to gravestone in the world-renowned Victorian garden cemetery.
Crucifixes, stone angels, graves and other stone monuments were also thrown over and smashed in the wrecking spree.
The Necropolis has also been targeted more than once by vandals on quad bikes, turning it into a dirt track.
Visitors to the city said they were disappointed that the landmark had been targeted again.
Jennifer Link, 65, was visiting with her husband Edward, 70, from Fife.
She said: "It's a shame. We think it's a beautiful place. It spoils it a bit and we're sad to see it but it's how things are these days."
Edward added: "I don't know what these people thought they were achieving. We had some visitors come across from Poland and the only thing they wanted to see was the Necropolis, so it's extremely popular."
Craig Cross, 48, had travelled from Edinburgh. He said: "Why would anyone make the effort to come up all this way and vandalise the monument?"
A Glasgow City Council spokesman said the graffiti removal team immediately treated the vandalism.
He said: "It is always extremely disappointing when anyone wilfully vandalises any part of our city. We work in partnership with the Police and GCSS to ensure vandalism is not a regular occurrence at the Necropolis."