In 1834, Parliament burned down, and the Standards of Measurement were melted or destroyed. So when there's no agreed-upon standard for length: how do you fix it? Also: how you can still publicly check the length of your sandwich. Filmed safely: https://www.tomscott.com/safe/ There's a correction to this video: the fraction on screen at 00:49 should be 1/299792458. Looks like I copied and pasted an extra 1 and didn't realise it. Apologies. You can see all the corrections for this channel at https://www.tomscott.com/corrections/ Story research by Jess Jewell SOURCES: Report of the Commissioners Appointed to Consider the Steps to Be Taken for Restoration of the Standards of Weight and Measure, 1841, https://books.google.co.uk/books?id=4xVSAAAAcAAJ A Collection of the General Public Statutes, 1855, https://books.google.co.uk/books?id=UDCaqwCgBKcC 🟥 MORE FROM TOM: https://www.tomscott.com/ (you can find contact details and social links there too) 📰 WEEKLY NEWSLETTER with good stuff from the rest of the internet: https://www.tomscott.com/newsletter/ ❓ LATERAL, free weekly podcast: https://lateralcast.com/ null ➕ TOM SCOTT PLUS: null 👥 THE TECHNICAL DIFFICULTIES: null