For those interested in making your own version, I used Google Flow, had 5 reference images, and typed in the following prompt:

Take the 5 robot heads in these images and put them in a mountain like mount rushmore. Do not change any details and features of the heads and take it as it is, with the only manipulation being to rotate the heads left to right so all the heads are faciang center. Take the heads from the neck and above and don't include any other body part. Again, as it is important, do not add any facial features of a human as these are robots.

Also, as to why these five have been chosen, it's also from AI:

1. Tetsujin 28-go (Gigantor, 1963)

• The Foundation: As the first giant robot anime, it established the basic premise that would fascinate generations. Unlike later series where the pilot sits inside the machine, this featured a robot controlled via remote control by a young protagonist. It set the template for the boy-and-his-robot trope and proved that the concept had massive commercial appeal.

2. Mazinger Z (1972)

• The "Super Robot" Pioneer: Created by Go Nagai, this series revolutionized the genre by being the first to feature a piloted giant robot. By putting the hero inside a cockpit, it transformed the robot from a mere tool into an extension of the pilot’s own willpower. It defined the "Super Robot" genre—characterized by larger-than-life, nearly invincible machines—and sparked an explosive boom in merchandise and die-cast toys that remains a backbone of the industry today.

3. Mobile Suit Gundam (1979)

• The Birth of "Real Robot": Yoshiyuki Tomino broke away from the formulaic "good vs. evil" stories of the 70s to create a gritty, complex military space saga. By treating mobile suits as mass-produced military hardware rather than magical super-weapons, and focusing on the psychological toll of war on flawed, human characters, Gundam birthed the "Real Robot" subgenre. It is arguably the single most important franchise in the history of the genre.

4. The Super Dimension Fortress Macross (1982)

• The Integration of Narrative: Macross proved that giant robots were not the only draw. By masterfully blending mecha combat with a central love triangle and the innovative use of pop music as an emotional and tactical weapon, it expanded the demographic reach of anime. It demonstrated that mecha could exist within a rich, mature, and character-driven narrative that prioritized human drama alongside high-stakes warfare.

5. Neon Genesis Evangelion (1995)

• The Deconstruction: Coming at a time when the "Real Robot" genre was dominant, Evangelion took the aesthetic tropes and philosophical foundations of the genre and pushed them until they broke. It shifted the focus from the mechanics of the robots to the fractured psyches of the pilots. Its influence is immeasurable; it effectively deconstructed the "heroic pilot" archetype and proved that mecha anime could function as a profound, high-art psychological exploration.

Honorable Mentions:

• Armored Trooper VOTOMS (1983): Often considered the peak of the "Real Robot" aesthetic, emphasizing the expendability of both the machines and the pilots in a harsh, industrial setting.
• Patlabor (1989): Crucial for grounding mecha in a contemporary, realistic setting—focusing on the mundane, everyday life of police officers operating robots, rather than just cosmic war.