375 years ago, the realm of Sweden founded the first European settlement in this area.
The King and Queen of Sweden celebrated the anniversary in Swedish and American history with a whirlwind tour of Philadelphia.
From the Liberty Bell to the Barnes Foundation, tourist got a glimpse of royalty as their Majesties took in the sights.
"I think it's great," said Madeleine Dali, from Paris, France. "I think it is part of the history of a country. I think it's very important to keep it."
Mayor Michael Nutter hosted a ceremony to welcome their Majesties King Carl, XIV and Queen Silvia.
"Sweden has a long history in the greater Philadelphia region," said Mayor Nutter.
The royal couple is in the United States to mark the 375th anniversary of the arrival of Swedish settlers and the founding of New Sweden in what is now the state of Delaware.
"Swedish settlers lived in the region 50 years before William Penn arrived on our shores in a settlement called New Sweden," said Mayor Nutter.
Philadelphia's official flag shares the same colors as the Swedish flag- a nod to those first settlers.
There are other reminders of the city's Swedish ties including the queen village neighborhood which is named for Sweden's Queen Christina.
King Gustaf said the first Swedish settlers came as merchants looking to trade and still today, his country looks to build on those long ago established relationships with the United States and Philadelphia.
"We have these good old relationships which I think are good for possibilities to expand trade between two countries especially to Philadelphia and this part of your great nation," said King Carl XVI Gustaf.
The king and queen also visited the American Swedish Historical Museum in FDR Park.
They will stop in Wilmington, Delaware and Washington, D.C. during their stay.