Ravenna is 12 km from the Adriatic coast and lies only 4 meters above sea level. Ravenna has buildings from the Roman era (Porta Aurea). The paleochristian and Byzantine complex from the 5th and 6th centuries are of enormous historical and artistic value. The Basilica Ursiana (altered in the 13th century) and the church of S. Giovanni Evangelista ( seriously damaged during world war two) are the most ancient buildings. The Mausoleum of Galla Placidia (5th Century) is still preserved in it’s original form, the inside being covered in classic mosaics. The neoniano Baptistery, known as degli Ortodossi (5th century) also holds classic mosaics.