The sparsely populated, volcanic spit of land that is the island of Hven measures 2.8 miles in length and 1.5 miles across, with a high plateau covering a good portion of that area — perfect dimensions for the famed astronomer Tycho Brahe. Accessible enough to bring in supplies from the mainland, yet remote enough to allow the astronomer to focus on his observations. Brahe had no telescopes, and observation and measurement of the movement of stars was still at a rather primitive level, but Brahe’s was nevertheless the first building constructed for the purpose of astronomical observation.

On this day, August 8, in 1576, the cornerstone for Brahe’s Urainborg observatory was laid down. Once completed, Brahe used the observatory’s many balconies and windows to accurately chart the positions of 777 stars — observations critical for later astronomers who built upon his work.

Brahe’s building was far from the utilitarian observatory ones of today.  Eighteen-foot-high walls surrounded Urainborg, and the entire facade was built out of ornate red brick with sandstone and limestone decorations. The observatory itself was part of a castle-like complex that included a cultivated garden kept by Brahe for many important household and medical plants.