File:A detail from part of an early 4th century AD mosaic depicting a basket of snails belonging to the floor of the Theodorian transversal hall, Basilica di Santa Maria Assunta, Aquileia, Italy (21410819623).jpg

The Crypt of Excavations is an underground archaeological area situated underneath the garden surrounding the bell-tower, where we can see archaeological remains of three different periods. Following the suggested route on the platform level we can see the cocciopesto belonging to the floor of the Theodorian transversal hall (beginning of the 4th century). At a lower level we see the mosaics of a domus, a Roman house, dating back to the times of Emperor Augustus (end 1st century BC -beginning 1st century AD). On a higher level there are parts of the mosaic and the foundations of the columns of the Post-Theodorian North (middle 4th century) destroyed by Attila in the year 452. Not immediately clear to understand are the remains of the warehouses dating back to the 3rd century, erected some time after the domus, and probably used until the works made byTheodore. Crossing the old threshold, we enter the TheodorianNorth Hall, where we can admire wonderful mosaics representing various animals (especially birds, but also the hippogryph) in strange positions (the lobster on a tree) or with particular objects (a goat with a horn and the pastoral) and rich of symbolic meanings referring to the truths of faith, the Christian virtues and eternal life in Paradise. Going all around the foundations of the bell-tower it is possible to admire other mosaics (the ram, the battle between cock and tortoise, the rabbit, the star of David) and the remains of the baptismal font of the second baptistery (of the Post-Theodorian North).