The Alte Nationalgalerie, or Old National Gallery, is a must-visit for art enthusiasts. It showcases a comprehensive collection of 19th-century art, including works by renowned German artists such as Caspar David Friedrich and Adolph Menzel. The museum's neoclassical architecture and stunning interior make it a visual delight, while its diverse collection offers insights into the development of German art during the Romantic and Impressionist periods.