Canada and the United States share the world’s longest undefended border, running along the 49th parallel from the west coast to Lake Superior and following natural boundaries for the remainder.
Denmark and Canada share maritime boundary in the Arctic and it runs in the middle of Nares strait through which runs Kennedy Channel. This 35 km wide strait separates Ellesmere Island from northern Greenland. The strait is home to two islands – Franklin and Crozier – which falls within the territorial waters of Denmark
The third and the contested island is within the territorial waters of both Canada and Greenland, an uninhabited barren rock of 1.3 Sq km, named after Hans Hendrik, an Arctic traveller. A theoretical borderline in the middle of the strait goes through the island. According to an international treaty, any island which is in 12 miles of mainland comes under the territory of that country which technically allows both Denmark and Canada a claim over the island.
The Permanent Court of International Justice of the League of Nations in a landmark judgement of 1933 ruled the island to be a sovereign part of Denmark. The League of Nations was replaced by the United Nations after World War II and Canada claims that this decision became irrelevant with the demise of the League of Nations.
The dispute between Canada and Denmark re-emerged in 1973 when Denmark and Canada started demarcating their borders through negotiations. They agreed on all other disputes except Hans Island which was then decided to be resolved later.
In return, the Danish Minister of Greenland visited the island and replaced the Canadian flag with the Danish flag. He took the Canadian whisky and replaced it with world-famous Danish schnapps.
This Whisky War continued until 2015, with both the armies taking turns in unfurling their national flags and placing their famous whisky for the other.
Canada and Denmark, both NATO allies, agreed to resolve dispute citing the presence of the Russian Army in the Arctic region during the cold war. On 04 May 2008, an international group of scientists from Australia, Canada, Denmark, and the UK installed an automated weather station on Hans Island. On 23 May 2018, Canada and Denmark announced a Joint Task Force to settle the dispute over Hans Island. A committee of Arctic experts was constituted to resolve the dispute peacefully. One of the main resolutions, they are thinking of, is to declare the barren stone island into condominium.
A condominium does not mean that the two countries are going to build a high-rise apartment building on the island, but it means that the island will be co-owned and co-managed by both the countries . Thus the will have both Canadian and Danish flags on it.