It was the smallest, least-populated and shortest-lived colony in the US. But despite being virtually unheard of today, it helped shape the nation's birth 250 years ago.

Ask most Americans and they’ll tell you that the United States started in Philadelphia on 4 July 1776 when the Founding Fathers signed the Declaration of Independence. Fittingly, the city is the epicentre of the US’s 250th anniversary celebrations this week, and as many as 1.5 million people are expected to descend on it for what will be the nation’s largest Fourth of July festival.

But chances are, almost none of those coming realises that the US’s political and ideological birthplace was once part of a little-known Swedish colony known as Nya Sverige (New Sweden). In fact, very few Americans (or Swedes) have any idea that there ever even was a Swedish colony in America