Roman Forum of Zadar is the largest on the eastern side of the Adriatic sea, founded by the first Roman Emperor Augustus, as shown by two stone inscriptions about its completion dating from the 3rd century.
Ancient Zadar (or Iadera as the Romans would say) was a Roman colony from 48BC until the disintegration of the Roman empire in the 5th century. After a violent earthquake in the 6th century, the buildings surrounding the forum were destroyed. The still standing elements and stones (then used to rebuild) were retrieved for various buildings.
Most striking is the decorative column marking the western side of the forum. Notice the chains still visible on the column. During the Middle Ages it was the 'pillar of shame' used to punish evildoers.
Continuing on the western side of the Forum, you come to the remains of the Capitolium which was an important temple consecrated to Jupiter, Juno and Minerva.
To round out an appreciation of Roman Zadar, take a look at Zadar's Archaeological Museum which displays artifacts from the Roman period as well as a scale model of the original Roman forum.References:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.