Lateral Thinking #03- Which Switch -

You have just purchased a giant mansion with a wine cellar in the basement. On the main floor, next to the staircase, are 3 light switches that control light bulbs in different parts of the house. You would like to know which one turns on the light in the wine cellar.

How can you determine which light switch is wired to the wine cellar by making a SINGLE trip to the basement and nowhere else? Note that this is not a trick question. You are alone in the house, the wiring is hidden behind the wall, and the rooms controlled by the three switches are not visible from where you are standing.

The solution is strictly in the manipulation of the light switches. You can do whatever you like with the switches, but once you go down into the wine cellar you need to know for sure which switch is for the wine cellar.