The most recognized Watcher in Marvel Comics, Uatu, has returned to the pages of Fantastic Four to reclaim his former spot on the Blue Area of Earth's Moon. But what secrets lie in the mysterious area?

With ancient ruins reaching beneath the planet, Marvel's Blue Area of the Moon remained a hidden relic of the past for decades. The Marvel Universe's moon was formerly the home to an ancient civilization long deceased, the first to arrive on Earth's moon with their city's remains underneath the lunar surface, billions of years before man. There would exist a terrain extending for miles as well as a breathable atmosphere for several alien species including humans, left behind by the Skrulls during their trial of the Kree and the plant-like aliens the Cotati. The Kree's test culminated in the savage aliens turning against the passive Skrulls, slaying the shapeshifters, and stripping the race of their advanced technology.

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Following the prelude to a prolonged Kree/Skrull War, the major attraction of the Blue Area of the Moon has become the private citadel of Uatu the Watcher, from which they observe the fascinating specimen of Earth. Within the colossal fortress lies a myriad of alien technologies, some capable of plunging an individual into the prehistoric past or an apocalyptic future. The X-Men's Wolverine would experience these technologies first hand when trespassing into the Uatu's property without an invitation. But an alien domain within a notable planet can only remain hidden for so long.

Dark Phoenix Comic Book

In an attempt to surpass the Soviet Union in space travel, the Fantastic Four would travel to their Earth's moon using a specially made rocket. On the trail of Russian scientist Ivan Kragoff a.k.a. The Red Ghost, the Fantastic Four would discover the alien Uatu and his ancient pad. But the Fantastic Four would be far from the last Earth-bound superheroes to visit the secret land. The final act of the X-Men's infamous Dark Phoenix Saga would occur on the Watcher's blue area. Though Uatu the Watcher would remain mainly uninterrupted from the X-Men's grand battle with the Shi'ar  Imperial Guard, Wolverine would fortuitously stumble into the Watcher's citadel.

The 1980s would bring another major development to the Blue of the Area Moon, introducing a new set of alien neighbors to keep the lone observer company. When their hidden city of Attilan located in the Himalayas was in danger of being wiped out from a boundless plague, the Inhumans Royal Family were in need of a breathable new safe haven, which the planet Earth could no longer provide. In desperate need of a location with natural air that is both fresh and clean, the Inhumans successfully transferred their city from Tibet to the unsoiled atmosphere of the Blue Area, with the help of the Fantastic Four.

With the Blue Area of the Moon again the property of The Watcher, it's yet to be seen if the expansion of the Fantastic Four location continues, allowing readers access into the Watcher's secretive quarters or whether they're left in the dark similar to Wolverine.

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Note: Comics for source (Fantastic Four #13 & 240, Uncanny X-Men #137, Avengers #133)