Aachen is known for the annual CHIO (short for the French Concours Hippique International Officiel),the biggest equestrian meeting of the world. So there are art works of horses allover in the city.
Aachen has the hottest springs of Central Europe with water temperatures of 74°C(165°F). The water contains a considerable percentage of common salt and other sodium salts and sulphur.
And of course, the Aachener Printen are known as a local specialty. (wikipedia)