Map of the „Freistaat Flaschenhals“ (“Free State Bottleneck”), 1919–1923.
<a href="//commons.wikimedia.org/wiki/User:Ziegelbrenner" title="User:Ziegelbrenner">Ziegelbrenner</a>.
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>. Source of Information: Ravenstein Radwanderkarte, 1923.