Mexico City commuters had quite a shock earlier this year when they found a seat molded with the outline of a penis and a male torso on a subway tain.

The "penis seat," which was marked as "exclusively for men," was actually a stunt by UN Women Mexico designed to highlight the issue of sexual harrassment that women suffer on public transport. A message on the floor below the seat read: "It is uncomfortable to sit here, but that is nothing compared to the sexual violence that women suffer on their daily journeys."

A video of the January stunt, showing travelers' reactions to it, was released on March 20 and has now gone viral, with over 1.7m views on YouTube. However, not everyone in the comments has approved, with some calling the seat sexist to men, and claiming it would stir up hatred between the sexes. Still, if what the video says is true, and nine out of 10 women in Mexico City has suffered from the problem, it's clearly an issue that needs urgent attention.