Hundreds of annual July 12 commemoration parades are taking place across Northern Ireland today.
A major security operation is in place with thousands of PSNI officers being backed up by police from across the UK.
One of the most contentious parades, in the Ardoyne area of Belfast, passed off peacefully this morning.
However the return leg of the the march has been banned by the Parades Commission - following trouble last year.
The PSNI Chief Constable Matt Baggott says he's hopeful there won't be a repeat of the violent scenes.
"Last night, yesterday evening passed off very well for us. [We're] very pleased, very grateful for people that went out, celebrated, and went home safely.
"Tensions have been high, but there's absolutely no reason why today shouldn't pass peacefully.
"Violence is a choice. The vast majority of people won't want that."