Lex's clone stood at the edge of the waterfall, observing the crystal clear liquid falling down with loud fury. On Earth, glacier water was usually considered one of the purest sources of water available. Here, glacier water held residual taint from some long forgotten contamination, making the water extremely aggressive in nature and dangerous to touch - not that Lex was considering bathing in that water or something.

Behind the waterfall, an arch was visible, coincidentally the perfect size to allow Lex through. But through the arch, he could only see shadows, as if it led to an unlit path.

Carefully, so as to not disturb the waterfall, Lex made his way around the water, and approached the arch, stepping in.

Fortunately, nothing crazy or abrupt happened. The arch leading back to the same waterfall was still behind him, and just to be sure, he stepped out and back in a few times. The arch stayed in place, and nothing in the surroundings changed.

Once his experiment was completed, Lex stepped into the arch and began to explore. It was dark, but the darkness wasn't mystical. Instead, it was because he seemed to be inside a large cavern.

From the tip of his finger, he summoned a faint light, illuminating the cavern. It looked entirely natural, if a little large, with countless stalactites and stalagmites. Somewhere in the distance, Lex could hear a drop of water dripping down into a puddle, but that wasn't what Lex was paying attention to.

Right in front of him, as if concerned that he wouldn't have been able to find it, was a large building of some sort, with spires around it, reaching the very roof of the cavern. There was a winding path that led to the entrance of the building, as if that wasn't suspicious at all.

This didn't look much like ruins, even if Kaemon had claimed that the ruins were well preserved.

Lex began to approach the building, keeping his senses spread wide on his surroundings to spot any and all abnormalities. Yet this was the most ordinary cavern Lex had ever come across, with no other surprises.

Though that was to be expected. Kaemon had said that all the knowledge he learned was depicted in murals that filled the actual ruins. If he completed the ruins task, he could retain the knowledge he had gained, and if he did not, he would forget.

But Kaemon also felt that the knowledge here was contaminated, for even after forgetting the knowledge, a fragment of the weight it caused stayed with Kaemon, and the others, causing a pressure that they still hadn't been able to overcome. That was the primary reason why Kaemon refused to enter another ruin. The weight of the knowledge he had learned and forgotten still weighed on him in an unbearable fashion.

Of course, the weight of the knowledge held in the ruins seemed to be of the most basic level, with citadels holding even greater secrets. But since Lex had no access to Citadels, he'd make do for now.

All the way until the entrance of the building, Lex encountered no obstacle of any sort, nor did he sense any malicious entity. It was, as if, the existence of the building automatically turned this into a safe space. Or maybe it was so dangerous that even the monsters of Abaddon had learned to stay away.

Lex took many precautions, just in case something went wrong, but he pushed open the door of the building and faced no problem. The interior, though, was like a totally different world.

It looked like Lex had returned to ancient Greece. Blinding sunlight shone down from the sapphire sky, revealing the breathtaking sight of a city sprawled across a hillside. Marble columns rose like frozen music, supporting grand temples etched with golden runes, and wide stone streets bustled with robed figures speaking in a tongue lost to time. Olive trees lined the paths, their leaves shimmering in the warm breeze, and distant lyres sang sweet, haunting melodies that drifted from open courtyards. It was as if the door had torn a hole in time itself, revealing a living echo of an ancient city, untouched and eternal.

Just as Kaemon had said, the ruins were… remarkably well preserved.

The air itself felt different, as if it too was from a different time. From where he stood Lex saw no murals, but he had no doubt that such a vast city was filled with them.

A marble staircase led down from the door that seemed to open in the middle of the sky, to the center of a semi-circle stage in the base of a large open-air theater.

He took the scene in and stepped down. Nothing remarkable happened, save that the air felt so fresh that Lex got goosebumps. One step after another, he descended the staircase, right up until he stepped on the stage.

From there, Lex noticed three things. He noticed a path - yet another path - starting from the theater stage and leading to the exit, no doubt taking Lex wherever he needed to go. The second thing he noticed was a mural. It was not visible from the stairs, but as soon as he stepped on the stage, he saw that the entire stage wall was actually a mural, revealing a complex scene. It would probably take a bit of observation to decipher.

Unfortunately, Lex could not focus on that, because most of his attention was diverted on the third thing he noticed. Kaemon told him that each set of ruins gave out a challenge. Completing the challenge would allow them to retain the knowledge they had gathered. Lex hadn't really thought about how the challenge would be given out. Now, he had an answer for the question he didn't ask.

Right in front of him, hovering in the middle of the air, was an illusory blue rectangle with the words 'Initiate Challenge' written on it. For some reason, Lex could not help but think that… the font on the text bore a great resemblance to the font of his own system!