Within the wood paneling of a hallway in the British House of Commons, there was a small brass keyhole.
Members of Parliament and staff walked past the tiny hole each day. The rare person who noticed the hole took it for an electrical cabinet.
Enter a team of historians planning the much-needed restoration of the Palace of Westminster, which is home to the House of Commons and the House of Lords. The oldest part of the estate, Westminster Hall, dates to 1099 and is still in use.