Name

Aliases

Originally built as a floating oceanography research station disguised to appear as a natural island in theAtlantic Ocean. It was first used byDr. Herman Frayne, a.k.a.Doctor Hydro, an insane ecologist. Frayne employed it as a lab and airbase from which to deploy hijacked aircraft. Doctor Hydro wanted to transform the hijacked passengers of five jets into amphibious merpeople. The active ingredient in his transformation catalyst was theInhumans' mutagenicTerrigen Mist, which he acquired from the renegade Inhuman hybridMaelstrom.^[2]

Following Frayne's death, the five-hundred victims of his experiment, known as theHydro-Men, stayed in residence on the island base, along with marine scientistDr. Walter Newell, aliasStingray. The Hydro-Men lived there for a few years untilDr. Reed Richards of theFantastic Four, working in conjunction with Inhuman scientists, discovered a way to cure the Hydro-Men.^[3]

After that time, Stingray used the facility as an oceanographic laboratory and as a residence for himself and his wifeDiane. When the U.S. Federal Aeronautical Association revoked theAvengers' flight privileges from their midtown Manhattanmansion, Dr. Newell invited the group to lease part of the island to create a private airfield on Hydro-Base, which was located only nine miles offshore from New York. The Avengers accepted his offer, relocating their supersonicquinjets to the floating island and constructing the UGABS, or Underground Airbase Shuttle, as a rapid means of transport to it from Avengers Mansion. The Fantastic Four also moved their largervehicles to the island at that time. As an Avengers outpost, Hydro-Base offered its airliner-capable runway, a Research and Development facility including several robots, and a quinjet hangar.^[4]

When Avengers Mansion was badly damaged by an attack by theMasters of Evil, the Avengers relocated entirely to Hydrobase.^[5] The mansion was later placed onto the island sometime later.^[6]

Hydrobase was sunk when robots created byDoctor Doom punctured the flotation tubes and caused an explosion.^[7]

The artificial island was salvaged and re-tasked into a floating instrument platform and surface connection forHydropolis.^[8]

Many years later, the Hydrobase was retrofitted, repurposed, and relocated to thePacific Ocean bySunspot as the headquarters of his newAvengers Idea Mechanics.^[9][10] This location served as the main base of A.I.M. as well as a decoy forAvenger Base Two, the headquarters where "the real work" got done.

When S.H.I.E.L.D. attacked the Avengers Island in retaliation for a war crime, Sunspot was forced to abandon the location and move all of A.I.M.'s operations and operatives to Avengers Two.^[1]

Alternate Realities[]

Counter-Earth (Heroes Reborn)[]

This complex was originally designed as an operations facility forS.H.I.E.L.D. by Stark Industries, and later hosted the Avengers headquarters.Seeking them out,Loki Laufeyson peered inside the building to see what his old foes were doing.^[11]

Former Residents[]

• Avengers
• Joseph Jennings
• Namor McKenzie
• Namorita
• Tamara Kurtz
• Avengers Idea Mechanics
  • Sunspot
  • Dr. Mandy O'Connor
  • Dr. Max Brashear
  • Dr. Toni Ho
  • New Avengers
    • Demiurge
    • Hawkeye
    • Hulkling
    • Pod
    • Power Man
    • Songbird
    • Squirrel Girl
    • Tippy-Toe
    • White Tiger

• Hydrobase's creator/designer could be theImperial Japanese scientist who created an artificial island duringWorld War II which housedShaggy Men.^[13]

• Fantasy
• Sci-fi
• Marvel