Brighton city centre was brought to a standstill as the annual Pride parade wound through the streets.
The procession set off from Madeira Parade and headed along the seafront, then down North Street, past The Pavilion and towards Preston Park.
For the first time, the gay, lesbian, bisexual and transgender event included a float especially for children.
The event attracts more than 100,000 spectators, who this year had to brave showers and drizzle.
Saturday's parade was the highlight of the week-long Pride festival, whose theme for 2008 is Pride Around the World.
Floats arrived in Preston Park at about 1300 BST, where the festivities will continue into the evening.
Sussex Chief Constable Martin Richards joined more than 100 police officers and staff from the UK to lead the carnival parade.
"Pride plays a real part in educating a minority who still feel that homophobic and transphobic behaviour is acceptable," he said.
"This is a significant event for the city and it is wonderful to be a part of it."
Among the scores of floats and walking tableaux were a Brazilian themed marching band, plus a cohort of Dolly Parton fans in revealing drag costumes.
Gavin Owen, the parade's chief steward, said: "There is such a wonderful atmosphere here today. People are always happy and jolly.
"Despite the weather we are all in high spirits.
"It shows everybody how diverse the community is and that we are all equal regardless of our sexuality."
A large team of volunteers has been planning the event for months.
Organisers said they hoped the festival, which began in 1992, would continue to help break down prejudice and ignorance.
Five Christian Voice protesters congregated on North Street during the parade.
Sussex Police officers made 11 arrests during the Pride event, nine of which were drug related.
The festivities continue all weekend, with a village street party in St James's Street and the surrounding area from 1800 BST until midnight on Saturday and from midday to 1800 BST on Sunday.
Most of the bars, restaurants and other businesses are supporting the event, with a sound system relaying local DJs on to the streets.
East Sussex County Council has been supporting Pride week by flying the Rainbow Flag at County Hall in Lewes.
"Our work in promoting equal rights in the workplace for the LGB community has been recognised by Stonewall and we are extremely proud of our standing in their top 100 employers," said council leader Peter Jones.