The Florence Baptistery was started in 1059 on the site of an earlier baptistery dating from the 5th century. Both are on the site of an older Roman structure.
The octagonal Baptistery faces the front of Florence Cathedral in Pza. del Duomo, It is faced with green and white marbles in geometric patterns on the exterior.
The domed interior is covered with magnificent mosaics showing the Last Judgement and some scenes from the Old and New Testaments.

Lorenzo Ghiberti's gilded bronze doors dating from 1424-52 can be seen in this image.