A Zoroastrian priest adds wood to a fire that has burned for centuries inside an Iranian temple. All photos: AFP
The fragrant holy fire "has been burning for more than 1,500 years", said Simin, a tour guide welcoming visitors to the Zoroastrian fire temple in Iran's central Yazd province.
Founded by the prophet Zarathustra, it was the predominant religion of the ancient Persian empire, until the rise of Islam
They venerate fire as a supreme form of purity. Alongside water, air and earth, the elements must not be contaminated by human activity, according to their faith.
Only Zoroastrian priests are allowed in the Yazd sanctum, covering their faces to prevent vapour and breath from contaminating the sacred fire
Today, the Zoroastrian community is estimated at around 200,000 people who live mainly in Iran and India.
Zoroastrians believe that "good thoughts, good words, good deeds" are the key to happiness and spirituality.
"Joy is essential in the practice of our religion," Simin, the tour guide, noted, mentioning multiple religious celebrations.
One of those festivals, Nowruz, marks the new Persian year and is celebrated to this day by Iran's overwhelmingly Shiite Muslim majority.
Tehran recognises Zoroastrians as a religious minority, granting them freedom of worship and representation in parliament
Zoroastrians are barred from careers in Iran's armed forces and cannot run for president.
A funerary rite known as "dakhma" was banned in Iran since the late 1960s for sanitary reasons as it involves exposing the dead bodies atop a platform known as "the tower of silence"
Among the community's most famous exiles is legendary Queen lead vocalist Freddie Mercury, born to a Zoroastrian family originally from India.
Zoroastrian priests have sought to open centres abroad, including in California in the US