ABERYSTWYTH, Wales — Bhumibol Adulyadej, Thailand’s previous king, will be cremated on Oct. 26 on a grassy patch of land in front of the Grand Palace in central Bangkok. He died a year ago, after a 70-year reign, and he is credited with transforming Thailand into a modern nation-state and unifying the country during times of political turmoil.

An army of royal artists and artisans has built for the occasion an elaborate set of structures that, in Thai Hindu-Buddhist cosmology, symbolizes the mountains, continents and oceans at the edge of the universe. The funeral pyre, precisely 50.49 meters tall, represents Mount Meru, which is thought to connect the human realm to the divine.

A select 7,500 people have been invited to the palace grounds for the five-day ceremony, but more than 250,000 mourners are expected to gather in surrounding areas. The government is reported to have spent between $30 million and $90 million on the preparations. Eighty-five replicas of the site in Bangkok have been erected across the country, as well as nearly 100 memorials throughout the world.

The cost, the crowds, the exquisite re-enactment of ancient spectacle — all of it may seem fit for a king, but the scale of the pomp signals a remarkable evolution. Although the main rituals of a Thai royal cremation have barely changed since the 14th century, the pageantry surrounding them has, reflecting the political concerns of each period. Over the last century or so, the Thai monarchy has gone from seemingly frugal to unabashedly rich — and it has managed that by casting King Bhumibol as a Buddha-like figure.