My sister had that problem coming back from a 6 week Geology Field Trip around France, Germany and Switzerland (they tried going to Liechtenstein but, being a Sunday, it was closed). When her group were on the ferry back to Blighty none of them could remember the English word for ‘milk’. They just sat there saying “What the hell is English for ‘milk'” – in English.
Additional: for fans of London’s peculiar secrets, I found this in the Guardian and it is totally Bryant and May-esque:
https://www.theguardian.com/artanddesign/2021/jun/29/inventive-vents-london-flues-grilles-our-hut
Don’t forget to follow the hot links in the article, either. 🙂