A single gold coin could fetch more than $1 million as ancient coin collection goes to auction after 100 years of secrecy

• A historic gold coin will kick off the sale of one of the most valuable privately owned collections.
• The 1496 King Hans Gold Noble coin is part of the prized L.E. Bruun collection, which is valued at $72 million.
• The collection has been kept in a secret location for years thanks to a stipulation in Bruun's will.

A rare Danish gold coin could fetch more than $1 million when it goes to auction next month, kicking off the sale of one of the most mysterious coin collections ever.