Suddenly, the world is plunged into an eerie, violet darkness. The temperature drops. Birds and other animals, bewildered by unforeseen night, start behaving strangely. Stars and planets appear in the sky next to the blotted-out Sun.

It is this awe-inspiring sight that has drawn people from all over the world to northern Spain on Wednesday to witness a rare total solar eclipse.

"People do get addicted to it because it is such a moving experience," said Lucie Green, one of four self-described "eclipse chasers" who spoke to AFP before the event.

Getting a glimpse of the Sun is particularly special for Green, a solar physicist at University College London who was ready to watch the eclipse from a boat off the Spanish island of Mallorca.

She is just one member of a growing community who plan holidays around seeing total solar eclipses, which can be seen in different places around the world every year or two.

Eclipse chaser Elizabeth Warning, a 51-year-old TV researcher in Australia, said seeing a total eclipse "feels like it's the end of the world... you're changed forever."

Warning had intended to travel from Sydney to Spain for Wednesday's eclipse, but cancelled her plans at the last minute out of concerns about the fires that have been ravaging the country.

An "extreme" wildfire risk has been issued for most of Spain on Wednesday, with temperatures forecast to hit 40 degrees Celsius (104 Fahrenheit) in parts of the northeast.

- 'Adrenaline rush' -

While a partial eclipse will be visible in most of Europe, North America and northwest Africa on Wednesday, eclipse chasers are purists in their pursuit of "totality" -- when the Moon completely blots out the Sun.

Totality is only visible in a narrow band of Earth, which usually requires intricate and expensive travel plans. However Wednesday's event -- the first total eclipse visible in mainland Europe this century -- has proved an easier trip for many.

Ryan Milligan, a solar physicist at Queen's University Belfast in Northern Ireland, has travelled for 12 different eclipses, to places as far-ranging as Siberia, Chile and the Faroe Islands.

On Tuesday, Milligan was in the Spanish city of San Sebastian, where 99.7 percent of the Sun will be obscured.

"Not close enough!" said Milligan, who was headed for the Spanish city of Burgos, where totality will last one minute and 43 seconds.

"A total eclipse is not something you see, it's something you experience," he told AFP.

"The temperature drops, the light and the shadows are all in the wrong place, the colours are muted, there's a 360 degree sunset, the animals go to sleep -- these things you cannot convey to people through a picture or a video or a news article," Milligan said.

"It's that adrenaline rush of trying to experience all that within a few minutes that pushes us literally to go to the ends of the Earth."

Then once the brief thrill is over, the chasers start planning for their next hit.

"It's a very expensive, very odd addiction," Warning said with a laugh.

Green went all the way to Antarctica in 2021, only to be thwarted by that common enemy of eclipse chasers: clouds.

"I've got about a two-thirds success rate," she said.

Sometimes it works out. Warning described how the "the clouds parted" at the last second in the Faroe Islands in 2015, allowing her to see an eclipse that people just hundreds of metres away missed.

Milligan was one of those in the Faroe Islands who saw only clouds.

"I was distraught... not least because they told me I would have seen it if I'd stayed in my hotel," he said.

Because they are travelling to the same place at the same time, members of this small community sometimes meet up.

For example, while driving in the extremely remote northwest of Australia to see an eclipse in 2019, Green said she bumped into Milligan.

- 'Wine and pintxos!' -

Jenny Winker, a 60-year-old retiree in St Paul, Minnesota, arrived in the northern Spanish city of Logrono on Saturday with nine family members.

"Enjoying all the wine and pintxos!" she told AFP hours before the event.

"If you've never seen a total eclipse, it is breathtaking."

Some chasers are already planning for a total eclipse on August 2 next year.

Near Luxor, home to the Valley of the Kings in Egypt, totality will last six minutes and 22 seconds -- that will be the longest eclipse humans will be able to see until 2114.

Experts warn that anyone viewing solar eclipses must wear special glasses to avoid damaging their eyes.