The main railway station of Palermo is Palermo Centrale which links to the other cities of Sicily, including Agrigento, Trapani and Catania, and through Messina and the strait to the rest of Italy. The railways also connect to the Palermo airport with departures every thirty minutes. The local university is the University of Palermo, the island's second oldest university. It was officially founded in 1806, although historical records indicate that medicine and law have been taught there since the late 15th century. The Orto botanico di Palermo (Palermo botanical gardens) is home to the university's Department of Botany and is also open to visitors. Palermo is twinned with:   In Robert Roswell Palmer and Joel Colton's majestic text-book for University education in the subject of history, A History of the Modern World Palermo is used to exemplify the south of Europe in context of the 1848 Revolutions, and Copenhagen for the opposite cardinal direction: ""...from Copenhagen to Palermo and from Paris to Budapest."" In this manner, Palermo is twinned to Copenhagen and reversed. People awarded the honorary citizenship of Palermo are:   "See also: "