On 3 September 1967, Sweden executed one of the most ambitious peacetime logistical operations in modern history: switching from left-hand to right-hand traffic in a single morning. Dagen H, as it was known, required years of planning, military coordination, and the cooperation of 4.5 million drivers. Clare Vale explores how this audacious plan worked, why accident rates actually dropped afterwards, and what it reveals about collective trust. The episode also visits the traditional founding date of San Marino in 301 CE, the world’s oldest surviving republic, examines the 2017 discovery of a Second World War bomb that forced 60,000 people to evacuate Frankfurt, and revisits the launch of eBay on 3 September 1995, allegedly beginning with the sale of a broken laser pointer to a collector. Four stories about human ambition, persistence, unfinished history, and the odd logic of markets.

• Intro Clare introduces the concept of a country switching which side of the road it drives on, overnight, with millions of participants.
• Dagen H: The Day Sweden Switched Sides On 3 September 1967, Sweden switched from left-hand to right-hand traffic. The operation required years of planning, military involvement, and a five-hour road closure. Despite public opposition in a 1955 referendum, the government proceeded. Accident rates dropped sharply in the days after the switch as drivers paid extraordinary attention.
• San Marino: The Republic That Outlasted Everything Traditionally founded on 3 September 301 CE by a Christian stonemason fleeing persecution, San Marino claims to be the world’s oldest surviving republic. It has remained sovereign through centuries of upheaval, never absorbed into Italy, and maintains an unusual dual head-of-state system.
• Frankfurt, 2017: A Very Old Problem On 3 September 2017, authorities in Frankfurt discovered a 1.8-tonne British Second World War bomb during construction work. More than 60,000 people were evacuated in the largest displacement in Germany since 1945. The bomb was successfully defused, but the incident highlighted how wartime ordnance remains a present danger.
• eBay: The Auction That Started With a Broken Laser Pointer On 3 September 1995, Pierre Omidyar launched AuctionWeb, later known as eBay. According to early company lore, the first item sold was a broken laser pointer for $14.83, purchased by a collector of broken laser pointers. The platform became a defining marketplace of the early internet era.
• Outro Clare reflects on collective trust, unfinished pasts, and the strange logic of human decisions across history.

• https://en.wikipedia.org/wiki/Dagen_H
• https://en.wikipedia.org/wiki/San_Marino
• https://www.bbc.co.uk/news/world-europe-41133740
• https://en.wikipedia.org/wiki/EBay
• https://www.theguardian.com/world/2017/sep/03/frankfurt-evacuates-60000-people-defuse-bomb-second-world-war