There are lots of cities that offer horse-drawn carriage rides, but few can compete with the elegant get-up of the horses and carriages we saw in Krakow.
There's a long line of carriages parked outside of Cloth Hall in Krakow's Market Square. You can have your pick. Different routes and destinations within the city exist; you can negotiate this with the driver.
I've found that a good time to do one of these rides is when you first get into a new city. A good driver generally also makes for a good guide; the experience is fun and a good introduction to your new destination.