Set sail with Oleif, the Viking. Make his boat move by learning all about matter and particles.

Halvor likes to collect rocks. Join him, and help him learn more about rocks.

This site from the Galileo Project of the Rice University provides an in-depth look at the historic problems figuring out longitude. Links are provided throughout this article along with pictures, making this a great site to check out.

A Map of Europe during the Crusades period showing the various lands and kingdoms including the German Empire, France, Kingdoms of Norway and Sweden, Republic of Novgorod, Kaptchak, Prussia, Saxony, Kingdom of Austria, Lombardia, the...