On a site once 25 times the size of the Colosseum, only 30 rooms of the 250-room palace can be visited, and by guided tour only.
The site was far smaller than the Colosseum, with 25 rooms.
mnli hypothesis: The site was far smaller than the Colosseum, with 25 rooms. premise: On a site once 25 times the size of the Colosseum, only 30 rooms of the 250-room palace can be visited, and by guided tour only.