The world’s second worst border mess is found in the southwestern part of the Netherlands. The small village Baarle is split between a Dutch part Baarle-Nassau and a Belgian part Baarle-Hertog.
Borders run criss cross through streets, houses and even bedrooms. To make things worse, there is not one Belgian enclave on Dutch territory, but there are 22 (yes: twenty two). And within some of the Belgian parts, there are even second-order Dutch enclaves. So there is a part of the Netherlands with a part of Belgium in the middle, in which we find again stretches of the Netherlands. Are you still following?
Not that both governments have not tried to resolve this unpractical situation. Territorial negotiations have been going on and off since the 14th century..
Baarle-Nassau/Baarle-Hertog is only surpassed by the Cooch Behar enclaves between India and Bangladesh.
Read more on wikipedia.