The "Twalft"

Massive Bonfires are built across parts of Northern Ireland ahead of today's celebrations to commemorate the Battle of the Boyne. The bonfires, which are built in areas with majority Protestant populations, are to commemorate the 1690 battle in which King William of Orange defeated the Catholic King James. They are lit ahead of the annual major Orange parades of the 12 July.
The pyres are built by piling up hundreds of wooden crates and car tyres. They usually have the Republic of Ireland flag on the top.
Parades
Lambeg Drums
Getting ready
That must be very unhealthy for the whole population, not to mention terribly smelly.