Uraniborg was an astronomical observatory and alchemy laboratory established and operated by the Danish astronomer Tycho Brahe. It was the first custom-built observatory in modern Europe, and the last to be built without a telescope as its primary instrument.

An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Historically, observatories were as simple as containing an astronomical sextant or Stonehenge.