3. Pompeii, Italy
Though Pompeii is now one of the most famous archaeological sites, the city was not demolished for modern development but by a natural disaster. The eruption of Mount Vesuvius in 79 AD buried Pompeii under layers of volcanic ash, effectively preserving its buildings.
In recent decades, however, as modern infrastructure expanded around the ancient city, many other nearby towns have been displaced or altered, causing the surrounding area to lose its historical charm.