In early nineteen sixty one the villain known as Nemo attempted to use ancient Atlantean technology to destroy Great Britain.  All he suceeded in doing was cause several sea quakes and raise a large spit of land up from the ocean depths.  High Justice, based in London at this time, surveyed this new island and gained permission from both the British and Irish governments to lay claim to it.  Over the next five years they constructed a base.

The Citadel had been constructed to be easily defensable, difficult to break into and equally difficult to escape from once security lockdown ensues.  It had been modified over the years to take advantage of new technologies and materials, and it's appearance changed as sections were added on, old ones modified.

The Citadel was built over a series of underwater tunnels that grant access to the ocean.  Here the group stored its three submersables, two of which were spoils from earlier cases against old enemies.  The entrances to these caves are as secure as any other entrance, as an old battle with Barracuda and his School of Doom taught the team to expect attacks from any quarter.

High Justice eventually retired as a team and The Citadel remained vacant for several years as it's legal owner, Brian Griffith, slowly removed all dangerous equipment, trophies and artifacts from it to more secure facilities.  Originally plans were made to turn the base into a museum of some sort but nothing ever came to fruition.  Then the former Vindicator known as Soleste, known to faerie folk as "The Barrow Queen", defected from Titania and Oberon's Ireland based realm and requested asylum under the British umbrella. She lay claim to High Justice Isle and The Citadel and renamed the place Solestia.

The Barrow Queen's relationship with the British government is a tenuous one.  There is nothing on paper and the government does not recognize her royal status, but at the same time there have been no efforts to evict her from the island and Griffith has legally turned ownership of the place over to her and her loyal minions  as well as providing technical support to keep power, heat and water running.  The presence of the faeries seems to have altered the landscape of the place, causing small woods to take root on the rocky soil.

Solestia makes money partly by limited tourism and by the creation of some of the finest needlework and tapestries ever seen.  A Solestian tapestry, knitted by dozens of faerie, can sell for hundreds of thousands.