These monumental figures are placed on the exterior of the Marienkapelle, a large chapel in the center of the market square in Würzburg. Adam and Eve face the market. The originals have been moved to the museum at Festung Marienburg, and can be found in the Riemenschneider gallery; these are replicas in place now.
See the detailed post for more photos of the original.
As you enter the Marienkapelle, look to the back of the nave towards the pipe organ; this work is on the rear wall to the right of the large wooden doors.