Tens of thousands of people have massed in the German city of Rostock to protest ahead of the G8 summit being held nearby next week.
The large crowd included many from anti-capitalist and anti-globalisation groups.
The streets of Rostock were transformed for the march, thought to be the largest gathering in the city's history.
But not all the protesters were quite so colourful. Many wore an all-black uniform to avoid easy identification by police in case trouble flared.
Some 13,000 police were out on the streets to oversee the proceedings.
Though most protesters moved peacefully through the city, by mid-afternoon violence had flared on the march's fringes.
Police said they came under "massive assault" by a small group of protesters. The authorities had warned of attacks by radical left-wing groups.
Violent protesters broke up paving stones and dug up cobble stones to use as missiles.
Vehicles were overturned and torched, sending a black pall of smoke over the area.
Police used chemical sprays to try to disperse the crowd. Later tear gas and water cannon were used to drive the trouble-makers back.