How can you cross over a seemingly invisible line (within Europe) and find yourself in a completely different country, where people speak a totally different language? What holds the languages in and keeps them so cleanly separate? How does that line, in some cases, a very fine line, keep 2 distinct worlds apart and stop them merging into each other - languages, cultures, identities, currencies, history, nationality and everything else?

Gamla Stan (Old Town) is Stockholm’s original city centre and consists of Stadsholmen island and the islets of Riddarholmen, Helgeandsholmen and Strömsborg. It is one of the largest and best-preserved medieval city centres in Europe and was founded in 1252. The historic centre and the adjacent island of Riddarholmen still feature cobblestone and pedestrian-only roads.

The Nobel Prize Museum is located in the former Stock Exchange Building on the north side of the square Stortorget in Gamla Stan. 

Kungliga slottet (the Royal Palace is on Stadsholmen (Stads Island) and is the official residence and major royal palace of the Swedish monarch (King Carl XVI Gustaf and Queen Silvia but since 1981 they have lived in Drottningholm Palace (10 km outside Stockholm). Changing of the Guard takes place daily at the Royal Palace during the summer months.

Storkyrkan is also called the Cathedral, or Church, of St. Nicolas. According to tradition it was built by the Birger Jarl, the founder of the city Stockholm, in 1264 on the highest point of the island Stadsholmen. Several coronations and royal weddings have taken place here in its over 750-year history.

Riddarholmen is often referred to as "the island of the Noble" or "Knight`s island".  For centuries, wealthy noble families lived on this island but  now most of the buildings belong to the Swedish judicial system. Riddarhuset (The House of Nobility) is a palace and an organization for the nobles in Sweden. Its objective is to preserve and maintain a historical heritage.

It is possible to visit this amazingly intricate 17th century building - the walls of the Session Hall are are decorated with the 2.326 coats of arms of the Swedish aristocracy.

https://www.riddarhuset.se/riddarhuset-english/

Riddarholmen Church, Stockholm's only preserved mediaeval abbey, is the burial place of the Swedish monarchs. With the one exception of Queen Christina, all succeeding rulers of Sweden from Gustav II Adolf (d. 1632) to Gustaf V (d. 1950) are buried here, including kings from the middle ages such as Magnus Ladulås and Karl Knutson Bonde (d. 1470).

The church is open during the summer season, with an annual programme of concerts.

The larger island of Södermalm from Riddarholmen.