These thermae (Roman baths) of Gijón are considered one of the most important sites in northern Spain. Campo Valdés are a site museum on baths dating from the Early Empire. They are located in front of the Church of San Pedro under Campo Valdés Gardens, at sea level. The baths were discovered in 1903, remaining hidden from the public until 1965.
Located outside the Roman walls, the baths consisted of two distinct units: the household area and the area of the thermae.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.