Tens of thousands of people gathered to see in the new year at Hogmanay celebrations across Scotland.
In Edinburgh an estimated 80,000 attended the annual party on Princes Street.
Glasgow hosted a ceilidh in George Square, open only to ticket holders, followed by a fireworks display.
Inverness had a huge free party at the Northern Meeting Park Arena, with the Red Hot Chilli Pipers, Peatbog Fairies and Blazin Fiddles.
Edinburgh's Concert in the Gardens, featuring Biffy Clyro, The Charlatans and Billy Bragg, was sold out.
Biffy Clyro guitarist James Johnston said: "It's a massive honour. We have never been through to Edinburgh for the Hogmanay celebrations and we have never done a gig on Hogmanay at all, so this is definitely a good place to start.
"It's the biggest party our country has all year."
People travelled to the Hogmanay event from all around the world.
Irina Rusina, originally from Siberia but who now lives in Germany with her English boyfriend, said: "It is my first time in Scotland and I love it. I'm completely enjoying myself.
"It is a lot warmer, but much more crowded than it is in Siberia," she said.
Student Pancho Welshy, from Paris, said he and his friends were travelling the globe to experience the best new year party.
He said: "This is much better than Paris. The atmosphere is great - really exciting. What can I say about Edinburgh? C'est magnifique!"
A candlelit concert took place at St Giles' Cathedral on the Royal Mile and the evening culminated with a fireworks display from Edinburgh Castle and Calton Hill.
Police said one person had been arrested at the event for a "minor disorder".
About 330 police officers patrolled Princes Street and the surrounding area.
Assistant Chief Constable Mike McCormick, of Lothian and Borders police, said: "Once again the revellers in Edinburgh impressed us with their behaviour and attitude.
"Only one arrest was made by our officers at the event, and we would like to thank everyone there for helping create a fun, safe atmosphere to welcome in 2011."
About 5,000 people packed into Glasgow's George Square to see in the new year.
They were entertained by Scottish traditional rockers Skerryvore and Celtic music legends Capercaillie.
Aberdeen City Council organised a free fireworks display from the roof of His Majesty's Theatre at midnight.
Hundreds of people also gathered at Stonehaven's annual fireballs ceremony.
Stirling Castle's event, which featured singers including Wagner Carrilho from the X Factor, ended with the city's "biggest ever" Hogmanay fireworks display at midnight.
A piper played at the Midsteeple in Dumfries from 2345 to 0015 GMT and revellers gathered for the bells at midnight.
The events are a draw to tourists from around the world and a boost to the Scottish economy.
According to the Scottish government, Edinburgh's Hogmanay alone generated an estimated £29m in 2009.
More than 25,000 people took part in a torchlight procession in Edinburgh on Thursday evening to kick off the city's new year festival in the capital.
The event, which started at Parliament Square, marked the beginning of a four-day celebration.
Organisers said the numbers of people attending Thursday night's event had been "record-breaking".
Edinburgh's emergency services and the city council have issued a number of guidelines warning revellers to stay safe, be sensible and keep warm and dry during the celebrations.