Construction began in 1248, but by 1560, political changes had taken place, and funds dried up. So all construction stopped until 1842.
There was a massive wooden crane on top of the south tower, that had already sat there for 150 years, when construction stopped. So the crane remained there until 1842. This crane became the symbol of Cologne and it dominated its skyline for 400 years. The timescales are mind-boggling. Entire generations lived and died, for four centuries, looking up at an idle construction relic from, even for them, ancient times.
Read the rest (and see pictures) here.