Close to the Catacombs of San Callisto are the large and impressive Catacombs of Domitilla (named after Saint Domitilla), spread over 15 kilometres of underground caves.
The Domitilla Catacombs are unique in that they are the oldest of Rome's underground burial networks, and the only ones to still contain bones. They are also the best preserved and one of the most extensive of all the catacombs. Included in their passages are a 2nd-century fresco of the Last Supper and other valuable artifacts. There are almost 150,000 bodies buried in the Catacombs of St. Domitilla.
They are the only catacombs that have a subterranean basilica; entrance to the catacombs is achieved through this sunken 4th-century church, at via delle Sette Chiese 282. In the past, the basilica had become unsafe, and was abandoned in the 9th century. It was rediscovered in 1593, and much of it was reconstructed in 1872.
References:The Roman Theatre of Mérida is a construction promoted by the consul Vipsanius Agrippa in the Roman city of Emerita Augusta, capital of Lusitania (current Mérida). It was constructed in the years 16 to 15 BCE. One of the most famous and visited landmarks in Spain, the Roman Theatre of Mérida is regarded as a Spanish cultural icon and was chosen as one of the 12 Treasures of Spain.
The theatre has undergone several renovations, notably at the end of the 1st century or early 2nd century CE (possibly during the reign of Emperor Trajan), when the current facade of the scaenae frons was erected, and another in the time of Constantine I (between 330 and 340), which introduced new decorative-architectural elements and a walkway around the monument. Following the theatre"s abandonment in Late Antiquity, it was slowly covered with earth, with only the upper tiers of seats (summa cavea) remaining visible.