DUBLIN (AP) — Record crowds celebrated Ireland's national holiday Thursday as a parade led by the country's most prominent disabled rights activist snaked its way through Dublin on St. Patrick's Day.

Parade grand marshal Joanne O'Riordan, who was born without arms or legs, beamed a joyous smile as she steered a special scooter past an estimated 550,000 people lining the route of the parade across the River Liffey to St. Patrick's Cathedral.

O'Riordan, who at 19 already has addressed the United Nations and embarrassed the government into reversing cuts to disabled services, led a parade that featured giant snakes, several St. Patricks, entertainers and animals dressed in every color of the rainbow, and dollops of irreverent humor.

Tourism officials said Dublin was experiencing its biggest tourist wave connected to St. Patrick's Day, which is the centerpiece of a four-day festival. Most Dublin hotels are booked solid through the end of the month as many stay through Easter, when Ireland commemorates the 100th anniversary of the Easter Rising, the ill-fated Dublin rebellion that inspired Ireland's 1919-21 war of independence from Britain.

Irish President Michael D. Higgins, who attended Thursday's parade with a sprig of freshly cut shamrock in his lapel, called on Ireland to embrace the idealism of the rebels of a century ago.

"When we Irish are at our best, we are a nation defined by a commitment to human rights, creative imagination and, at a global level, the upholding of freedom from oppression," Higgins said in a video address.

In his St. Patrick's message the leader of Ireland's 4 million Catholics, Archbishop Eamon Martin, expressed hope that Europe would show greater sympathy to people fleeing war and poverty.

Martin described Patrick — a Briton originally brought to Ireland as a slave who returned to spread Christianity across the pagan island — as an undocumented migrant, too. He said Patrick's life story mirrored "the growing numbers of people who find themselves displaced and without status in our world."

Dublin braced for possible drink-fueled trouble as many parade spectators headed for the city's Temple Bar entertainment quarter, where police and private security firms mounted 38 checkpoints to keep crowds under control.

Online:

Presidential message, http://bit.ly/1R52jtH