St. Katharinen, on the edge of the old town facing the Zollkanal and Speicherstadt, is the medieval mariners' church of Hamburg and one of the five great Hauptkirchen of the city. The 14th- and 15th-century brick-Gothic structure was gutted by Allied bombing in 1944; the post-war restoration kept the original tower (rebuilt with its copper-domed Baroque top) and rebuilt the nave in a quieter, almost austere mid-century style.
Pirates were once forbidden burial in the church's cemetery, but Klaus Störtebeker, the legendary 14th-century pirate executed in Hamburg in 1401, has a small memorial plaque inside. Free organ recitals run most Wednesdays at lunchtime. The church is around the corner from the Speicherstadt and makes a quiet stop between visiting the warehouse district and walking back to the Rathausmarkt.