1111 is the traditional number for all things related to carnival 🎉 in the Rhineland river area of Germany 🇩🇪 and The Netherlands 🇭🇺.
Carnival starts on 11/11 (Nov. 11th) at 11:11h. There are 11 people in the carnival "committee", etc.

Helau & Alaaf are the traditional carnivals greetings there.