Almost every popular account of a Norse temple traces to one passage, written by a man who never visited, about a place he wanted destroyed.
The passage. Adam of Bremen, writing in the 1070s in his history of the archbishops of Hamburg-Bremen, describes a temple at Uppsala "entirely covered in gold", holding statues of Thor enthroned in the centre with Wodan and Fricco beside him. He reports a festival every nine years at which nine males of every living kind, men included, were sacrificed and their bodies hung in a grove beside the temple, "so holy to the heathens that each tree in it is thought divine". A Christian informant, he says, counted seventy-two bodies hanging together.
Why it needs handling carefully. Adam was in Bremen. He wrote from the reports of others, some of them decades old. His work advances the claims of his archbishopric to authority over Scandinavia, and describing Swedish practice as maximally barbarous served that end directly. He was writing about a religion he wanted suppressed, for an audience that would fund the suppressing. A later scribe added a marginal note, the famous line about a spring where a living man is drowned, which some manuscripts absorb into the text. None of this makes him a liar, and Swedish paganism plainly did involve sacrifice; it makes him a hostile secondary source whose specifics cannot be taken at face value.
What excavation found. No golden temple. There was a building beneath the medieval church, but nothing supporting Adam's description of it. What the ground did hold is considerable in its own right: the three great mounds, sixth-century, containing high-status cremations with gold and imported goods; a substantial royal hall on a terrace; and, uncovered in 2013, two rows of wooden posts running for close to a kilometre across the plain, forming a monumental approach to the site. Nobody had predicted them and no written source mentions them. The excavated Uppsala is a major ceremonial and royal complex, just not the one in the book.
The site is in use again, and the distinction matters. Swedish organisations practising Forn Sed, the old custom, hold ceremonies at Gamla Uppsala, and Nordic pagan bodies have legal recognition in Sweden, Iceland and Denmark. This is a twentieth-century reconstruction assembled from medieval Icelandic literature, archaeology and comparative material, and its own practitioners generally state that plainly rather than claiming an unbroken line.
The distinction cuts both ways and both matter. Modern Heathens are not the continuation of what Adam described, and should not be treated as though they were: and equally, a revived religion is a real religion, and describing Norse paganism purely in the past tense misdescribes what is happening at the site on a given weekend.