Complex sentence: Lichterfelde became part of Steglitz around 1900, and Dahlem became part of Zehlendorf, both were included into the city of Greater Belin in 1920 and are today united in the new borough of Steglitz-Zehlendorf.
Split into simpler sentences: Lichterfelde became part of Steglitz around 1900, and Dahlem became part of Zehlendorf. Both were incorporated into the city of Greater Berlin in 1920 and are today united in the new borough of Steglitz-Zehlendorf.