Thousands of Orangemen are marching across Northern Ireland today for the annual Twelfth demonstrations.
Orange lodges were due to gather at 18 demonstrations throughout the province.
The two flagship demonstrations are being hosted by Comber and Randalstown.
The Independent Orange Order’s main parade takes place in Ballymoney.
The Orange Order director of services, Dr David Hume said they hoped to encourage many tourists to attend the parades.
“This is the sixth anniversary of our Twelfth Tourist Flagship programme and we believe that it has been a huge success and has helped to develop the potential of the parades,” he said.
“We know that more than half a million people either take part in the parades or watch them — that is a huge proportion of the population.
“For very many people it is the biggest day of the year.”
In Belfast, up to 250,000 people were expected for the annual Orange Order parade, due to start at 10am.
For the third consecutive year the city centre shops are open until 4.30pm. In Belfast shoppers can enjoy the Northern Ireland Food Produce market in the grounds of the City Hall.
Mr Hume added: “We have been working closely with the Northern Ireland Tourist Board and Tourism Ireland to attract more visitors to the province in July and they have been extremely helpful.”
The grand master of the Grand Orange Lodge of Ireland, Edward Stevenson, said: “It has special significance in the history and culture of our country and is enjoyed by massive crowds.
“There is no other single event that can produce crowds like the Twelfth.
“There are 18 different locations in Northern Ireland, all |with distinct characteristics that make it such a special day of religion, culture, music and pageantry.
“We want people to visit the Twelfth and enjoy the atmosphere for themselves and we believe that the work we are doing with the tourist authorities is crucially important.”
Assistant Chief Constable Alistair Finlay appealed for the public to avoid anti-social behaviour.
“There will be in excess of 500 parades across Northern Ireland, the vast majority will take place peacefully,” he said.
“We will have a large number of police officers out to facilitate people to ensure they can enjoy the day and there doesn’t have to be any resorting to disorder or violence if people keep a cool head, stay calm, engage in conversations.”
Mr Finlay added: “There is a significant police operation. This is one of the most demanding days throughout the year in policing in Northern Ireland.”
“We continue to work closely with the loyal orders and other partners to discourage drinking alcohol in and around parades and other public events.
“This can lead to anti-social behaviour, people feeling intimidated, assaults and other crime.
“It is all communities that pay the price, so I would urge people to think before they drink.”