MADRID/REYKJAVIK — The grand stellar spectacle of the year has arrived. Millions of people gathered in Iceland and northern Spain to witness Europe's first total solar ​eclipse in 27 years on Wednesday, with Spanish officials warning people to avoid areas where a heatwave has raised the risk of wildfires.Major viewing locations in parts of Iceland, northern Spain and a small corner of northeastern Portugal will be in the path of totality, when the skies go momentarily dark as the sun completely disappears from view — creating a rare sunset eclipse for some, especially observers in Spain.Authorities were expecting up to 6 ‌million visitors in mostly rural areas within the eclipse's path across the north of Spain and the Balearic Islands, said Juan Cruz, Spain's Secretary of State for Science."I hope that tonight will see the emergence of a wonderful generation of astrophysicists," he said. "It's such a special moment."A total solar eclipse occurs when the moon moves between the sun and Earth, casting a shadow on our planet that completely blocks the sun’s light from some areas of the world.In Portugal, the national team are not playing, the prime minister is not addressing the country, there are no COVID-19 press conferences, but the country will still stop at the same time to look at the total eclipse of the Sun.Around 19.30, in the Bragança region, the total eclipse of the Sun will occur, meaning day will turn into night as the Sun is covered by the Moon. This will be an astronomical spectacle nobody will want to miss, not least because it is highly unusual and the last total eclipse visible from mainland Portugal took place in 1912.But the eclipse will not be the only phenomenon to amaze this evening. From 21:30 on Wednesday, about an hour after the eclipse ends in mainland Portugal, there will also be a meteor shower. These meteors, known as the Perseids, leave a trail of light as they pass through the atmosphere.This is an annual meteor shower, usually active from mid-July until the end of August. The peak generally occurs around 12 and 13 August.The eclipse will be visible across the country but it will not look the same in all regions. The total eclipse, which corresponds to 100%, will be visible only in the Montesinho Natural Park, in Bragança.The deep partial eclipse, with between 92% and 99% coverage, can be observed throughout mainland Portugal.On the islands, the Azores and Madeira, the percentage is much lower, between 74% and 77%.The eclipse will begin at around 18:33 and end at around 20:23, lasting roughly two hours. Its maximum will be reached close to 19:30. The total eclipse phase lasts just 25 seconds.The eclipse will be quickly followed by the sunset in Spain, making the event particularly alluring.The uncanny sensation when day briefly turns into twilight and some ​animals fall quiet as the moon passes directly between Earth and the Sun was often treated as an omen in the past, a cosmic struggle or a sign of divine ​power.Now, Spain sees it as a chance to showcase seldom-visited regions and draw tourists away from its overcrowded beach resorts, while also rolling out a massive police ⁠operation and public safety campaign to prevent them causing wildfires.Interior Minister Fernando Grande-Marlaska told reporters 25,000 police officers had been assigned to guarantee security around the eclipse observation while nearly 100 planes and ​helicopters were also being deployed.He called on citizens to follow the eclipse from the hundreds of observation points set up by authorities and abide by the restrictions set up around some parks. "Let's not forget ​that the wildfire risk is very high, it's extreme due to high temperatures," he said.Lola Guerreiro spent the night in the mountains near Arco de las Salinas in eastern Spain, home to Galactica — Europe's largest educational astronomy centet — as well as the Javalambre observatory, after making the long drive from Extremadura to view the eclipse."Watching a total solar eclipse has been a dream of mine for many, many years, and I didn't want to miss the chance ​to experience it, even though it meant a seven-hour journey," she said.The Iberian Peninsula last saw a total solar eclipse in 1912. It is ‌set to experience ⁠another one on August 2, 2027, and an annular eclipse in January 2028, completing the so-called "Iberian Eclipse Trio."In Iceland's capital Reykjavik, glasses to allow people to look at the phenomenon without damaging their eyes have been sold out for days as the Nordic country of roughly 400,000 people expects to welcome up to 80,000 visitors.A narrow path of totality will reach Iceland's westernmost coast at about 5:44 p.m. (1744 GMT), before the moon's shadow races east.Totality will last up to 2 minutes and 13 seconds in the far west, though most cities will see shorter periods of ​darkness. Authorities have warned of heavy traffic and ​urged viewers to arrive early.US space agency NASA plans to fly a high-altitude WB-57 aircraft from Iceland to follow the moon's shadow, and NASA-funded teams will launch balloons to study how the sudden darkness and cooling affect the lower atmosphere."This is a once-in-a-lifetime ​experience," said Karen Williams, 51, who was visiting from Britain. "I love the outdoors, and so I wanted to come and see the eclipse and ​just experience it."Skies over Iceland were overcast on Wednesday with the Icelandic Met office predicting clouds and rain for much of the path of the eclipse, adding that the best chances of breaks in the solid cover were expected in the northwest of the country.Aside from casual observers, the event also draws "eclipse chasers", ⁠enthusiasts who ​crisscross the globe to be in the path of totality whenever an eclipse occurs.Gordon Telepun, a retired plastic surgeon and ​amateur astronomer from the US who has photographed six total eclipses, said he would watch from the island of Mallorca because Spain checked all the boxes for eclipse chasers.Meanwhile, a partial eclipse, in which only some of the sun’s light is blocked from view, will pass over the northern US, Canada, much of Europe and northwestern Africa.