In 1248, construction began on the Cologne Cathedral. The builders who laid its foundations knew the work would outlast them.

They were right by a margin that strains comprehension: the cathedral was completed in 1880, more than six centuries after the first stone was set.

Generations of workers, architects, and patrons contributed to a structure none of them would ever see finished.

They built anyway, because they understood something that modern life tends to obscure: some of the most important work a person can do is work whose completion belongs to someone else.