Košice turned out to be a very pleasant surprise! It's billing as Slovakia's second largest city and a major industrial center didn't sound very attractive, but circumstances required a visit and I am quite glad they did.
Košice has a wonderful historic center, with a large public square that is free of cars (always a plus) and lined with well-maintained buildings from the city's Medieval and Renaissance eras. The square is dominated by the magnificent Gothic (and Baroque) Church of St. Elizabeth, said to be the largest church in Slovakia. Around the square are shops and restaurants and interesting pedestrian tunnels that lead through many of the buildings to the surrounding streets. Away from the center is a large city park (though we didn't linger there long during our visit on a cold day in January).
Throughout history, Košice has been as much Hungarian as Slovakian, depending upon where the border happened to be drawn at the moment. Even as late as 1938-1944, Košice was part of Hungary (as a result of an agreement with Adolf Hitler while both Hungary and Slovakia were allies of Germany). After World War II, Košice was restored to Slovakia and Slovakia was returned to the reconstituted Czechoslovakia.
Today, Košice has the conveniences of a modern city, yet still retains much of the charm from past centuries (at least in the historic center of town). It is easy to get to by train and well worth a visit.