Rusty key has probably been stuck in this 19th century lock for a long time.

Museum of Physical Security

Nicholasville, Kentucky

Harry Miller was the son of a master locksmith. He was only 26 when he made a name for himself by cracking the burglar-proof safe at the White House, after the only person with the combination had died (The First Lady needed her jewels for an upcoming visit from the king and queen of England).

When all else fails.

Recognizing Harry's talent, the government put him to work during World War II teaching spies and law officers what Harry called "the science of lock manipulation." He began collecting locks as teaching tools, and the collection grew as he toured Europe after the war, visiting hundreds of embassies, horrifying ambassadors with the ease with which he opened their supposedly impregnable safes and vaults.

In early 1956 Harry fell and broke his legs. This gave him time to organize his lock collection, which he displayed at a trade show later that year. It was quickly recognized as the largest in the world, but it remained rootless until 1997, when it was moved to the new headquarters of Lockmasters Security Institute, founded by Harry as the world's first locksmithing school. Satisfied that his 12,000 locks finally had a home, Harry died the following year at age 86.

A small sample of Harry Miller's lock collection, largest in the world.

Bombs have locks, too.

Harry's collection is called the Museum of Physical Security, although "museum" is a bit of a stretch. Labeling is sparse, and doesn't offer much insight except to those who already know a scissoring lock bolt or dimple key when they see one. Still, the variety of weird mechanisms and gizmos is impressive, and helps the average tourist appreciate how much effort and expense has gone into keeping people away from other people's valuables.

The exhibits fill showcases in the building lobby, spill down the hallways, and line the walls of the lunchroom. Students wanting inspiration or insight can browse the collection, but it's also open to the public, and it's free.

Amateur safecrackers can try their luck on these bad boys.

Artifacts on display range from elegantly crafted Victorian Era vault locks with mysterious mechanical gears and dials, to bawdy coin banks with slots in rude places.

Even describing this bank would be wrong.

A showcase of prisoner shackles and a chastity belt is framed by artful arrangements of hundreds of keys, padlocks, and handcuffs. There's a lock from the jail in Tombstone and from a Russian nuclear warhead; keys belonging to Buckingham Palace and Hitler; and murky glass tubes labeled "poison gas for safes." Clearly there is much here to reward visitors with a careful eye and a lock picker's patience.

According to a yellowed newspaper clipping displayed in the museum, Harry was so good at safe cracking that he designed a lock that no one could manipulate -- including Harry, who had it installed on his house, lost the combination, and had to break his way in. We would expect that similar high-end security surrounds Harry's collection, and are reasonably certain that this is one museum whose rare objects will never be stolen.