The Roman theatre of Cádiz is an ancient structure discovered in 1980. The theatre, which was likely built during the 1st century BC and was one of the largest ever built in the Roman empire, was abandoned in the 4th century and, in the 13th century, a fortress was built on its ruins by order of King Alfonso X of Castile.
The theatre featured a cavea with a diameter of more than 120 meters, and could house some 10,000 spectators. The theatre was one of the few Roman structures of ancient Hispania mentioned by classical authors, including Cicero and Strabo. Excavations in the site have also found remains of a quarter dating to the taifa period, Almohad houses and 17th century pits.
References:House of the Blackheads (Melngalvju nams) is a building situated in the old town of Riga. The original building was erected during the first third of the 14th century for the Brotherhood of Blackheads, a guild for unmarried German merchants in Riga. Major works were done in the years 1580 and 1886, adding most of the ornaments.
The structure was bombed to a ruin by the Germans June 28, 1941 and the remains demolished by the Soviets in 1948. The current reconstruction was erected from 1995 to 1999. Today the House of Blackheads serves as a museum and sometimes concert hall.