A 15th Century merchant's hall built when Norwich was England's second richest city is reopening after restoration work which cost almost £2m.
Dragon Hall was built to trade goods from around the world
Dragon Hall, the only building of its type in Western Europe, was built by wealthy Robert Toppes in 1430 to sell goods imported from around the world.
Many medieval trading halls were built by merchants' guilds. The 400-year-old hall is the only one built by one man.
It is named after the dragon motif engraved into the ceiling.
Manager Stephanie Potts said: "The medieval hall had not been built to last as a memorial.
"The fact that it is still here is almost a miracle," she said.
The Grade I listed hall, owned by Norwich City Council and managed by the Norfolk and Norwich Heritage Trust, is considered one of the most important historic buildings in Norwich and Norfolk.
Work on the restoration, which cost £1.8m, began in January 2005.
Visitors will be able to see displays on three floors telling the story of Robert Toppes and the building's place in the history of Norwich.