 Travertine limestone was found much closer, around Tivoli, and was used from the end of the Republic; the Colosseum is mainly built of this stone, which has good load-bearing capacity, with a brick core.Other more or less local stones were used around the empire.The Romans were extremely fond of luxury imported coloured marbles with fancy veining, and the interiors of the most important buildings were very often faced with slabs of these, which have usually now been removed even where the building survives.