Frankly, I very much doubt it. Aldrin is almost certainly referring to an anomalous (if most likely geological) feature on the surface of Phobos, the larger of Mars' two moons.
Discovered by independent Mars researcher Efrain Palermo, the "monolith" is an uncharacteristically tall, shadow-casting structure that awaits further exploration. Interestingly, this 2007 space news piece refers to the Phobos Monolith (as it's come to be called) as a target for a future mission. (The Phobos Monolith isn't to be confused with a similar feature photographed on the Martian surface.)
To learn more about Palermo's Mars research, click here. For more on the Aldrin controversy, refer to Cabinet of Wonders.)
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