A must on any Italian travel plan, Milan is a combination of historic structures – some stemming back to Celtic rule - new architecture, and restored monuments that received extensive damage during the Second World War. Rent a car from Milan Linate Airport and tour both Milan's traditional structures, and its modernist skyscrapers that adorn the city's skyline. The fourth century Colonne di San Lorenzo is one of the city's oldest structures, and its Roman ruins are still well preserved. One of Milan's most recent buildings is the Bosco Verticale, forested skyscrapers, designed by Italian architect Stefano Boeri.