[21] The military demands on what became Germany's largest fortress presented a significant obstacle to urban development, with forts, bunkers, and wide defensive dugouts completely encircling the city and preventing Expansive phase; this resulted in a very densely built-up area within the city itself. Cologne prospered during the Weimar Republic https://schwimmbadbau54219.win-blog.com/10799830/top-jeweils-fünf-schwimmbadbau-köln-urban-news