Hundreds of naked cyclists and skaters have taken to British streets as part of a global protest over the dependence on oil.
Up to 500 riders travelled routes in London and Brighton as part of the World Naked Bike Ride.
The event was first held in 2004 when more than 120 riders cycled naked through London and Edinburgh.
Last year 250 people took part in the event, making it the UK's biggest naked protest.
'Fun but serious'
A spokesman for the event said the protest was over car culture and the vulnerability of cyclists using roads.
He said it also recognised the "power and individuality of the human body", and denied the mid-afternoon start time deterred some cyclists because it clashed with the England vs Paraguay World Cup game.
London rider Melissa Evans, 33, said: "The ride is fun, but has a serious side as well. By going naked, we show our vulnerability as cyclists in the traffic.
"I'd like to see London become a city for cyclists and not cars. Most of my friends would love to ride bikes here in London, but they're afraid of the motor traffic.
"Ban cars within the M25, and most Londoners would choose to get around by bikes because they're the safest, fastest, healthiest form of transport."
Sussex Police used police patrols and CCTV to monitor the cyclists in Brighton.
A spokesman said that no-one had dared to bare completely and consequently no arrests for nudity had been made.
Other naked bike ride events took place elsewhere in the UK, including Bath, York and Edinburgh.
Around the globe cyclists took off their clothes and hit the road in countries such as Poland, the US, Russia, Japan, New Zealand, Spain and South Africa.
In the Czech Republic, a handful of young cyclists took to the streets of central Prague for an hour, wearing paint - and in some cases not even that.
More than 60 men and women took to York's medieval streets on Friday evening in a bid to encourage riders to take part in the London ride the next day.
Jesse Schust, one of the riders who took part in that event, said they were warmly supported by revellers heading to bars in the city centre for a night out.
He said: "It was great. We were really well received and it was a lot of fun to be involved in."