Built in 1902, the Thorp Building was originally home to Thorp Doors, which made heavy-duty sliding metal-clad fire doors. During World War II, General Mills Mechanical Division occupied the building to secretly manufacture highly classified military equipment — namely the Norden Bomb Sight and the Ryan Listening Device, the predecessor to the Black Box. The Norden Bomb Site project was under of a veil of secrecy well into the war and was part of a then-unprecedented production effort on the same scale as the Manhattan Project. Protected by the FBI and CIA, two guard towers remain on the property from the secret operations. Now you can ponder the long storied history of the building over a Tattersall cocktail.