There's no mistaking it, and as I first arrived in Bordeaux, i found myself saying, C'est une…read moregrosse cloche! It's huge and it's an important symbol of Bordeaux, built in the 15th century. At the time, it was rung to signify the beginning of the grape harvest, but also to warn of fires and for special holidays.
It's a gorgeous landmark and a remarkable slice of history.
There are short tours available.