AIB by BUN's National Park Thread, what UNESCO World Heritage Sites have you been to? Any in particular that you like more than others?
Austria: Historic Centre of the City of Salzburg, Historic Centre of Vienna
Canada: Rocky Mounain Parks, Waterton Glacier International Peace Park, Old Town Lunenburg
Czech Republic: Historic Centre of Prague, Historic Centre of Ceský Krumlov
Egypt: Islamic Cairo
Greece: Acropolis, Athens, Meteora, Archaeological Site of Epidaurus
Holy See/Italy: Historic Centre of Rome, Vatican City, Church and Dominican Convent of Santa Maria delle Grazie with "The Last Supper" by Leonardo da Vinci, Historic Centre of Florence, Venice and its Lagoon
Spain: Alhambra, Generalife and Albayzin, Granada, Parque Güell, Palacio Güell and Casa Mila in Barcelona, Historic City of Toledo
UK: Tower of London, Westminster Palace, Westminster Abbey and Saint Margaret's Church
USA: Mesa Verde, Yellowstone, Glacier Bay, Grand Canyon National Park,
Everglades National Park, Independence Hall, Redwood National Park, Mammoth Cave National Park, Great Smoky Mountains National Park, Statue of Liberty, Yosemite National Park, Hawaii Volcanoes National Park, Pueblo de Taos, Waterton Glacier International Peace Park, Carlsbad Caverns National Park
My favourites are Yosemite (my second home practically, been there over 100 times easily) and two sites in Spain, the Alhambra and the City of Toledo.