In Welsh, the word for week is wythnos, which literally means “eight-nights”. Historically, the week started and ended with night. – WTF Fun Facts
Source: https://en.wikipedia.org/wiki/Eight-day_week
welsh
WTF Fun Fact – Sandcastle Record
A Welsh community built 2,044 sandcastles on the Whitmore Bay beach to break a Guinness World Record. – WTF Fun Facts