It is here where the Sava River meets the Danube (Dunav), and its because of this position, Belgrade is fittingly referred to as the Gateway to the Balkans and the Door to Central Europe. Belgrade's long and storied history is suggested by its architecture, which varies from Byzantine and Ottoman to neoclassic and romantic buildings in the older neighborhoods, and from Art Nouveau to neo-Byzantine design in New Belgrade. Grandiose coffee houses, quirky sidewalk ice-creameries and smoky dens all find rightful place along Knez Mihailova, a lively pedestrian boulevard flanked by historical buildings all the way to the ancient Kalemegdan Citadel, crown of the city. Deeper in Belgrade's bowels are museums guarding the cultural, religious and military heritage of the country. Outspoken, adventurous, proud and audacious, its gritty exuberance makes it one of the most happening cities in Europe.