An estimated 20,000 people joined a Belfast rally on Saturday in support of marriage equality in Northern Ireland.

Demonstrators marched from Ulster University to City Hall, where they listened to speeches.

After Ireland last month became the first nation to legalize such unions through a referendum, Northern Ireland became the last country in western Europe where gay couples cannot legally marry.

“In 2005, history was made when Northern Ireland became the first place in the UK to hold a civil partnership,” the Irish Congress of Trade Unions (ICTU) said. “Ten years later, with every other part of these islands recognizing marriage equality, citizens in Northern Ireland have effectively been left behind.”

Amnesty International, another organizer, said the province was now the “last bastion of discrimination against gay people in these islands.”

Many politicians and local celebrities attended the rally, including Gary Lightbody, lead singer of Snow Patrol, and actress Bronagh Gallagher.