Royal Towers are a 'center of command' in Goodgame Empire.
Royal Towers may be found in the Great Empire. They are able to be attacked and captured. When captured, the Royal Tower provides a 20% attack bonus to the owner and their alliance members when attacking a Capital or Trade Metropolis.
The effects given by the Royal Tower are stackable - having multiple Royal Towers will further increase the attack bonus given to the owner and their alliance members. If the owner of the Royal Tower leaves their current alliance, they will lose control over the Royal Tower, and it will become reowned by robber barons.
There are currently no variations of the Royal Tower present in the kingdoms of the Everwinter Glacier, the Burning Sands, or the Fire Peaks. However, owning a Royal Tower in the Great Empire still provides the attack bonus when attacking Capitals in those respective kingdoms.
Similarly to Resource Villages, Monuments and Laboratories, the Royal Tower does not have an interior to build upon. The arrangement of soldiers and tools may be altered freely with the same mechanics as an ordinary castle. It comes with a built-in Castellan that is uncustomizable.