Cathedral of Our Lady of Strasbourg, one of the finest examples of high Gothic architecture, built between 1176 and 1439.
It was the world's tallest building from 1647 to 1874, and is the 6th tallest church in the world,
and the highest still-standing structure built entirely in the Middle Ages.

And it's so high it's almost impossible to photograph in its entirety, without converging verticals!