Surrounded by French territory, the Spanish town of Llívia became the unlikely center of a diplomatic dispute in the 1970s when road signs sparked an international conflict.

In the Belgian-Dutch town of Baarle, borders run through houses, shops and streets. A murder investigation reveals why local authorities sometimes need a surveyor before a detective.

France and Italy have argued over the exact location of their border on Mont Blanc since 1860. Emperors, kings, disputed maps and modern tourism all play a role in this long-running alpine controversy.

Within the European Union lies a self-governing monastic republic where women are still prohibited from entering. An extraordinary territory shaped by faith, tradition and centuries of autonomy.

Just off the French coast, the island of Sark preserved a feudal system well into the modern era. Lords, vassals and political intrigue collide on this unique Channel Island.

Mexico appears to have lost an entire island. The disappearance of Bermeja had major consequences for maritime borders and access to valuable oil reserves in the Gulf of Mexico.

Once home to more than 30,000 people packed into a tiny area, Kowloon Walled City existed in a legal gray zone between British and Chinese authority, becoming one of the most densely populated places on Earth.

On Cyprus, British sovereign territory remains a legacy of colonial history. The episode explores the unusual borders and political arrangements that still shape everyday life on the island.

China, Taiwan, Vietnam and the Philippines all claim parts of the Spratly Islands. Beneath the tropical scenery lies a strategic struggle involving oil, military bases and competing national ambitions.

For a historic international trial, part of the Netherlands temporarily became Scottish territory. The extraordinary legal arrangement made Camp Zeist a unique experiment in cross-border justice.