The town of Baarle is home to one of the most complex geopolitical borders in the world, consisting of Baarle-Nassau in the Netherlands and 22 Belgian enclaves known as Baarle-Hertog, which themselves enclose seven Dutch counter-enclaves. This intricate patchwork originated from medieval treaties, land swaps, and sales between the Dukes of Brabant and the Lords of Breda. Today, the international border cuts arbitrarily through streets, cafes, backyards, and individual residential homes.
To determine which country a house legally belongs to, local authorities rely on the 'front door rule' (voordeurregel): a building's official nationality, tax jurisdiction, and address are dictated solely by the location of its main entrance. If the international border intersects the front door directly, the building receives two house numbers—one displaying a Dutch flag icon and the other a Belgian flag icon. Over the years, clever property owners have exploited this rule for financial benefit; moving a front door just a few feet sideways can dramatically alter property tax rates, business closing hours, or building regulations.
During the COVID-19 pandemic, some local stores found themselves half-open and half-closed due to differing national lockdown policies on either side of the shop floor.