Thousands of Protestants are marking the contentious Apprentice Boys Parade in Northern Ireland, marching through the mainly Catholic area of Londonderry.
The march, which has sparked unrest in the past, is symbolic of the fragile peace in Northern Ireland.
Protestants in the historically divided region want closer ties with Britain, while most Catholics favour a united Ireland.
Al Jazeera's Tania Page reports from Belfast, where a similar but smaller march has taken place.