Note many major tourist spots are only open during late spring and summmer and during closed times can only be viewed from the outside.
KastelholmA castle located in the northern part is worth paying a visit. Partly a ruin today, it was founded in the 1380's and home to many Swedish kings who reigned the combined kingdom of Sweden and Finland from this place. There are guided tours, also in English.
Jan Karlsgarden Open Air Museumvery close to Kastelholm castle, it has a number of traditional Aland buildings moved from other areas. Entry was free in 2008, although a fee was charged to visit the prison museum on the same site. Also has a tourist information center and a good restaurant and cafeteria.
The fortress of Bomarsund(http://www.goaland.net/in...) was built by the Russians during the years 1830-1854. The establishment was thoroughly ruined during the Crimean War when attacked by the allied English-Frenchmen. On the other side of the channel, next to the bridge of Prästö, is a small museum where pictures and objects from Bomarsund are on display.
Postvägen(http://www.postvagen.com/...) The Mail Road dates back to Queen Kristina´s days in the 17th century, when the Swedish postal service of that time was organized. Today the Mail Road looks different but it is still very much alive.
The 4-mb POMMERN (http://www.mariehamn.ax/P...) in the West Harbour in Mariehamn serves as a memory of the great fleet of sailingships, who once had the town as their homeport.