That's what Austria's newspapers would like to know.
Several have published full-frontal photos of a mysterious subway patron — dubbed the "Vienna Venus" — riding the rails with nothing but a pair of boots and a smile asking their readers to identify her or at least the purpose of her pubic indecency.
One of the papers has even offered the woman a free photoshoot if she agrees to reveal the only thing she hasn't yet: Her name.
Absolutely nothing is known about the modern-day Lady Godiva, who boarded the Vienna U-Bahn near the Kardinal-Nagl-Platz station, and remained aboard for several stops before departing without saying a thing.
"I couldn't believe it when she stepped on the train and when some people grabbed their mobile telephones and started taking pictures she didn't object," an eyewitness told the Austrian Times. "In fact she even seemed to be posing for the camera."
Most passengers were far less concerned with the woman's nudity as they were with the possibility that she might catch a cold. Vienna has seen temperatures drop near freezing, and some parts of the country have been experiencing heavy snowfalls.
Wiener Linien, Vienna's public transit operators, took the spectacle in stride, saying, "We know that everyone has a different perception of temperature. We do not believe that it so warm in our subways that you have to undress."
[photos via Facebook]