The city of Sigtuna located at lake Mälaren in the north of Stockholm is the oldest still existing city in Sweden. All over the city archaeological excavations can be found, most of them being rune stones from the vikings, that settled there between the 6th and 11th century.
Rune stones are pretty much comparable to what we would call a tombstone today. To remember the dead, the stones are decorated with ornaments and inscriptions. At the time of the vikings, runic alphabets were widely used to write various Germanic languages mostly in Scandinavia.
Still today letters like Þ, which is called thorn, are used in the written language of Iceland. One of the stops on my road trip there was the national park Þingvellir, where the Þ is represented by a th when written with western letters.
Sigtuna, however, is definitely worth a visit. On a sunny summer day you can have a walk around the city, enjoy homemade cake in Tant Bruns Kaffestuga and relax at the lake.