In downtown Rome, close to Gregorian University, there lies a college for American students. A college in Roman terms is not a school but a place where students of various Roman universities live.
It being in Rome, the college had no air-conditioning. So, if you wanted to sleep during hot summer nights, you had to keep your windows open.
On one such night all the American students living there were awaken when a Roman man yelled out, "Maria, la chiave! Maria, la chiave! Maria, la chiave!" That's Italian for "Maria, the key!"
After Maria finally opened her window in the building across the street from the college, and threw the key out the window, the man unlocked the door, got in, and everything was quiet again.
Alas, the next night the man came back, and again yelled out, "Maria, la chiave! Maria, la chiave!". And so it went, night after night.
The Americans got quite annoyed, but they had lived in Rome long enough to know they could not just yell "shut up!", let alone reason with the guy.
So, they got together and collected all the old keys they could find, keys to locks long forgotten somewhere back in America. That night, when they heard "Maria, la chiave!" echoing down the ancient street of Rome, they waited for Maria to open the window. The same moment Maria threw the key out her window, the Americans tossed their collection of keys right at the noisy man. It took the man a while to figure out which of the "chiavi" (keys) was the right one to get to Maria's house.
Never again did the Americans hear anyone yelling, "Maria, la chiave!