Thailand's late King Bhumibol Adulyadej will receive a lavish send-off this week during a spectacular five-day funeral centered around a cremation at a gilded pyre in Bangkok's historic heart on Thursday.

Steeped in centuries of royal tradition and overseen by strict palace protocols, the elaborate $90 million ceremony will draw an estimated quarter million Thais to bid farewell to the "father" of the nation, who died last year aged 88.

Here's a few things to know about the funeral of a king revered as a demi-god who reigned for seven decades.

- The site - 

At the heart of the cremation complex is a 50-metre (164-foot) high funeral pyre symbolising Mount Meru, the allegorical centre of the universe in Buddhist, Hindu and Jain cosmology.

The gold-painted structure is adorned with dozens of intricate sculptures of animals, deities and mythical creatures from Buddhist and Hindu lore.

Pride of place will go to sculptures of the late king's beloved dogs.

Arranged symmetrically around the main tower are eight smaller structures representing the mountains surrounding Meru -- and a possible nod to Bhumibol's title as the ninth monarch of the Chakri dynasty, or Rama IX.

The vast site, nearly a year in the making, is studded with references to the king's welfare projects, including a small rice field and an irrigation wheel.

Bhumibol's body is kept in a separate coffin to the symbolic Royal Urn, which will be carried up a ramp on a golden chariot to the pyre. Both the urn and coffin will be cremated, allowing his soul to pass into the afterlife according to Buddhist belief.

- The ceremony - 

While sombre, the funeral is also a celebration as the late king ascends to heaven, with music and traditional dancers a key part of the ceremony.

The funeral formally begins on October 25 with a Thai Buddhist religious ritual. It will be led by Bhumibol's only son King Maha Vajiralongkorn, known as Rama X.

The following day the Royal Urn will be carried from the Grand Palace by bearers in striking traditional garb, flanked by drummers and soldiers.

On its way to the cremation site it will pass tens of thousands of black-clad mourners who are expected to bow and prostrate where possible.

A bank of monks will lead Buddhist prayers throughout the day-long ritual.

As dusk falls, the king and other royals will lead the laying of sandalwood flowers at the urn. 

The cremation itself will take place at 10:00 pm (1500 GMT) when Rama X will light the pyre. 

Three days of ceremonies to remove royal relics from the ashes will follow. The ashes will be taken to the Grand Palace while the relics will be enshrined in two temples.

- The guest list -

The funeral procession will be headed by the king, Rama X, with his sister Princess Maha Chakri Sirindhorn leading the rest of the royal family.

It is not clear how much of a role Bhumibol's wife Queen Sirikit will play, as she has been in ill health for years.

Power players from Thailand's junta and the all-important privy counsel will also be prominent in the procession.

Royals and dignitaries from over 40 countries will attend the cremation, including Britain's Prince Andrew, Japan's Prince Akishino and Princess Akishino, Queen Maxima from the Netherlands, the King and Queen of Bhutan and US Secretary of Defence James Mattis. 

Officials estimate that some 250,000 Thais will crush into the surrounding roads, while television sets will relay blanket coverage of the event.

The meticulously-planned funeral comes with a long list of guidelines for attendees in the country where all things royal are tightly controlled. 

Photographers are prohibited from taking direct shots of the king, while male journalists have been ordered to shave their beards and moustaches. 

- How will tourists be affected? - 

Swathes of Bangkok's historic centre will grind to a halt on cremation day, with roads shut around the Grand Palace, but some public transport to the site will be free.

Tourists are not expected to wear black like most Thais have done since the king's death in October 2016, but visitors have been asked to dress and behave "respectfully".

Nightlife will be toned down throughout the funeral period, although alcohol consumption has not been banned outright.

Many banks and businesses -- including the ubiquitous 7/11 stores -- will close for much of the cremation day on Thursday in an unprecedented mark of respect.