Market Island: The Island That Changes Every 10 Feet Due to a Border Blunder

• Market Island, a 3.3-hectare island between Sweden and Finland, has a unique border history.
• A lighthouse was mistakenly built on Swedish land, leading to a land exchange in 1981.
• The border now resembles an inverted 'S' due to the agreement, with no change to coastline or fishing rights.
• The island's border is marked by 10 deep holes in rocks due to harsh weather conditions.
• Sweden and Finland conduct joint surveys every 25 years to adjust the border due to changing sea waves.