One of the earliest two-story cities of the world in Akrotiri, Santorini

The destruction of Pompeii by the eruption of Mount Vesuvius in A.D. 79 has been preserved in ancient times by an eye witness account, namely that of Pliny the Younger. The literary evidence and amazing finds from the site has made Pompeii one of the most well-known archaeological sites in the world. It should be noted that Pompeii (and Herculaneum) are not entirely unique, as at least one other site it the ancient world has been destroyed by a volcanic eruption. The settlement of Akrotiri is one such site. Unlike Pompeii, however, no literary evidence for the destruction of Akrotiri is available to us. As a matter of fact, the city was only discovered by an archaeological excavation conducted in 1967. ( source )