This week Helsinki becomes the first Nordic city to host the world's oldest sci-fi and fantasy event, the World Science Fiction Convention (Worldcon).
The five-day conference begins with a blacksmithing workshop on Wednesday morning at the Helsinki Fair Centre and ends on Sunday with events focusing on archaeology, 3-D printing and Disney comics.
Guests of honour at the 75th anniversary Worldcon include the Jamaican-born Canadian writer Nalo Hopkinson, American novelists George R. R. Martin and Walter Jon Williams as well as Finland's Johanna Sinisalo, whose best known book has been published in English as Not Before Sundown and Troll: A Love Story.
Martin, the most hotly-anticipated guest, is the author of the series A Song of Ice and Fire, the basis of the hit HBO television show Game of Thrones.
Martin is one of the world's best-selling authors, with Forbes magazine last year estimating his annual income at 12-15 million dollars.
On his website, Martin calls Worldcon "the heart and soul of SF fandom," adding that for him "it's home away from home".
Martin, who visited the local Finncon event in 2009, is to take part in Friday's Hugo Award gala and panel discussions on Thursday, Saturday and Sunday. Thursday's panel focuses on invented religions.
Martin will also sign books on two – and only two – occasions, on Thursday at 2 pm and Saturday at 4 pm.
On his site, Martin lays out the ground rules for fans, saying: "For those of you who want books signed, please, bring them to one of my two listed autograph sessions. I will NOT be signing before or after panels, at parties, during lunch or breakfast or dinner, at the urinal, in the elevator, on the street, in the hall. ONLY at the autograph table. If the lines are as long as they usually are, I'll only be signing one book per person."
Walter Jon Williams, who has been a major figure in sci-fi since helping to develop the cyberpunk subgenre in the 1980s, has published more than 30 books including a number of prize-winners and bestsellers. He tells Yle that he's delighted to be on his second visit to Finland – the homeland of his Minnesota grandparents on both sides.
Event organiser Eemeli Aro says he has been pleasantly surprised by advance ticket sales. As of Monday, nearly 6,000 full five-day passes had been sold, with roughly one third going to Finnish fans.
Aro says that the event, which is held in a different city each year, has attracted between 3,500 and 6,500 attendees annually since the 1980s. So the Helsinki Worldcon is already shaping up to be one of the biggest ever.
Worldcon was inaugurated during the 1939 New York World's Fair, and has been held annually since 1946, mostly in the US.