St Patrick's Day parades underway

The country's biggest St Patrick's Day parade is underway in the capital.

The Dublin city parade is starting out at Parnell Square, and will travel down O'Connell Street, over O'Connell Bridge, up Dame Street and finish at St Patrick's Cathedral.

Around 500,000 people have lined the streets for the event, while up to 3,000 people took part in the parade itself.

Brave New World from @waterfordspraoi @Irish_Ferries and their giant spider! pic.twitter.com/1leYWaDk41

— St. Patrick's Festival 🇮🇪🐍☘️💚 (@stpatricksfest) March 17, 2015

St. Patrick blessing the good folk at the parade today. @stpatricksfest in #Dublin this afternoon pic.twitter.com/zYw0xAUs9e

— CllrAnthonyConnaghan (@CllrAConnaghan) March 17, 2015

The #Dublin #stpatricksday parade is in full swing! #lovedublin #stpatricksfest pic.twitter.com/nFnIZAdEBM

— Girl in London (@wanderbliss) March 17, 2015

The Cork city parade is starting at Parnell Bridge at 1pm this afternoon. The parade will then travel down South Mall, Grand Parade, and from Patrick St to Merchants Quay

Broadcaster and Cork native George Hook is this year's Grand Marshal.

Meanwhile, an alternative to other St Patrick's Day events across the country will be held in Dublin this afternoon.

Organised by singer Frances Black, Sober St. Patrick's Day takes place in the Gresham Hotel between 3:30pm and 7pm and will provide family-friendly, alcohol free events celebrating the best of Irish music, dance and entertainment.

The idea behind the event is to "Reclaim the true spirit of the day" and honour Irish Artists.