Protection in the form of iron bars on top of a mesh covered wall inside the Edinburgh Castle. In ancient times, especially when the castle was under siege, these wells were the only source of water in the castle and when there was a shortage, then the siege would start coming to an end. The Edinburgh Castle is a historic structure, with the royal castle dating back to the time of the kind David I from the 12th century. The Castle is built on a volcanic high, called the Castle Rock. The Castle was very important in the medieval ages, when there were conflicts to ensure Scottish independence from England. However, by the time of the 15th century, the importance of the Castle as the site of political power and dispute had reduced, and over the centuries, this importance reduced. After the crown of England and Scotland was unified in 1603, this decline in the importance of the castle reduced further. It was only in the last 200 years that there was an effort to do restoration of the castle and emphasize its historical importance.
The Castle dominates the skyline of Edinburgh, especially because it is built on a higher platform than the rest of the city, being built on a volcanic high. The castle height made it a good defensive platform, but the hard rock on which it was built also made it difficult to get water through wells.
The importance of the Castle for Scotland is very high, with the castle being a recognizable symbol of the city of Edinburgh, and it is used in the logos of many institutions, used on the banknotes issued by the Royal Bank of Scotland.