This was not a belief of mine but of a friend who lives in Budapest. There are several bridges over the river Danube and one of them is followed by a tunnel. My friend believed that the tunnel is there so that people can push the bridge into it in the evenings, else someone would steal it at night.
A childhood belief about in the street

others believed things like this
- That there was an underground tunnel linking New York to San Francisco.— Christophe Chang
- I used to believe that the Lehigh tunnel in Pennsylvania was created by Superman.— Holz
- I used to think underground trains actually descended into the tunnel, like a rollercoaster.— Natasha
- My friend's sister believed the lyrics to Gazza's "Fog on the Tyne" were "Fog on the dinasaurs mine all mine"— Suzanne
- I once told a friend of mine that if you held in a smelly burp, it'd turn into a fart. She believed me.Anon
- If you hold your breath and make a wish under a highway tunnel it will come true....I still hold my breath :)— aj