The round tower in copenhagen.

Rundetaarn as it is called in danish, is the oldest functioning observatory in Europe. The tower built by the Danish king Christian IV in 1642 is 36 meters tall, which back then was enormous. What makes it unique in European architecture is that it is round , and even more so that instead of a stair case, it has a spiral walk way winding around a hollow column 7 1/2 times, measuring 209 meters from bottom to top. The entire spiral is constructed from brick vaults plastered with lime ,and then lime washed with pit lime. As allways this gives a very special light (that is when the lime wash has been applied properly to achieve the very intricate crystalline structure, necessary to make the pit lime last and perform its maximum.)
Today only amateur astronomers and regular visitors use the tower for its original purpose, and since the professionals left the tower, it has been used for a variety of things, one being a uni cycle race, maybe inspired by the Russian czar Peter the great, who in 1716 rode his horse to the top.
I visited Rundetaarn on the 8th of January 2009, and i can recommend visiting if you should ever visit the old Copenhagen.
Lars Hansen.

Vikings

Most people do not associate vikings with plasters, but nevertheless most viking houses were plastered inside. The mix was a dung-clay mix, and spread over a lattice work made of sticks. This provided not only draft proofing, but also temperature and humidity control as we know clay plasters do in today's houses.
Most vikings were farmers when they were not raiding, but what we usually hear about my ancestors are stories about their barbaric warfare. And with good reason, the vikings were truly great, not in height but in how far they were able to reach and conquer. These squat little human beings (seldom measuring more than 5 1/2 feet ) traveled far. The Swedish mainly went through the Russian rivers and as far as Greece, and the Danish and Norwegian vikings went more south and westerly to places such as Ireland, England, Spain, Italy, France and even as far as to the part of north America which today is U.S.A. Some of these destinations became permanent settlements such as the Normandy, which was clearly given its name by the men from the north (nor man).
I just visited the viking ship museum in Roskilde, where a mix of ancient and recently built ships are displayed. These ships are a major piece in finding out how the vikings were able to travel as far as they did,since the common long ship were quite commonly reaching top speeds of 14 to 15 knots.
Lars Hansen.