Tranquil Reinickendorf is a mix of modern housing estates like Märkisches Viertel and tiny, historic villages like Wittenau. Expansive Tegeler Forst is a nature reserve with trails, home to Schloss Tegel, a mansion dating to the 16th century and the one-time residence of naturalist Alexander von Humboldt. Large Tegeler See lake is popular for sailing, while the smaller Flughafensee is known for its secluded beach.