"PLACES OF POWER: Describing Arcane Sites Found Across the Continent" is basically a travel guide, but does finally give us actual descriptions for locations which before only existed as markers in the map.

(It actually goes over more than 5 locations, don't worry)
-

Yep, imperials seem to indeed generally believe Lizardmen are just warm climate beastmen.
-Ziggurat of Dawn: It's close to Skeggi, but norscans have learned never to raid it, going instead for distant targets.A flame of Chotec is kept burning within to cleanse chaos-touched artifacts. There's a rumor about it granting the power of the sun, so multiple people have become bacon trying to use it to mimic the Flame of Asuryan. It seems to be slowly dwindling. It is guarded by the Keeper of the Flame, a unique Lizardman spawn who is always born in time to replace the previous keeper.
-Stellar Pyramids of The Southern Skies: Their tiers are ringed instead of rectangular or square. There's three of them, and they track the moon,stars and sun. The tiers actually rotate like gears, but they do so with such slowness that the human eye can't tell. Slann meditate in their shadow but not inside or atop them, something apparently unique. They can be used to tell the future, but the main one is all wonky and unreliable since a dark elf sorceress used it.
-Head Monoliths of the Fallen Gods: A series of giant stone heads look out toward the sea. Their designs are unique but they were still created by the Lizardmen. They Lizardmen don't tend to them or worship them, so its unclear what the "gods" they represent might be to begin with.
-Lake Xuhua: Basically an expy of the irl
Lake Guatavita. Except massive and filled with so much gold it glows in the night. Anyone who dives into the lake is trapped. All they can do is hammer helplessly against the surface as their lungs burn out. So the lake is filled with tons of gold, bloated corpses and sunken buildings.
-Wellsprings of Eternity: The Lizardmen believe the Wellsprings were once important to the Old Ones, a place where their silver sky chariots would come to prepare for journeys across space, but it want all wonky when Mazda changed the lay of the land around it to curbstomp a bunch of druchii. They had to carve a massive stelae to retether it to the Geomantic Web. Drinking from it gives you visions.
-Marks of the Old Ones: Nazca Lines expies. It is apparently something the Lizardmen built to try to reconnect with the Old Ones, like SOS signals. The Centinels of Xeti, on the other hand are like telescopes, actively looking for them. Kroxigors still clean them up, but otherwise abandonned.
-The Amaxon: What you'd expect from the Warhammer Amazon River.
-Piranha Swamps:When invasion seems likely, Skinks will damn sections of it to starve and frenzy the fish, releasing them just at the moment the foe is passing through,
-The Great Confluence: The hearland of Lustria, a set of massive waterfalls with pyramids floating on top of them. It's the meeting place the Slann use the few times they meet in person. Two of the temples honor Tzunki and Xokha. But the main one is abandonned and its glyphs obliterated, its sealed and not even terradons use it as a perch. Apparently the glyphs might have looked like a hooded figure or a bell (maybe Skaven stuff?) but no one is sure.
-Gwakmol Crater: Site of the biggest victory against the Skaven by the Lizardmen. They captured thousands of ratmen on its slopes and Tehenhauin used it in his biggest sacrificial revelry ever. It's filled with snakes and stained red. The ratmen never dare approach it. The altar at the center of it is older than Sotek tho, and no one knows what it might have been before.
-The Emerald Pools: Fountain of Yoith expy, the Slann bathe in them often.
-Beujuntae:Entrance to a great vault forgotten even by the Lizardmen, it is constantly moving and impossible to track. Inside are kept great golden discs, within which daemons are trapped since their defeat during the Great Catastrophe. It's basically a nuclear silo with no map to it.
-The Volcanic Isles: Some of the greatest lizardmen artifacts, like Gor-Rok's mace, were forced in the smaller island (Spitting Serpent), using the volcano as a forge. The Fuming Serpent is inactive and a pilgrimage place for the Cult of Sotek.
-Sentinels of Xeti: Basically radiotelescopes for the winds of magic. The Slann in charge of them is as close to depression as a lizardman can be. Once they piked up a transmision from an Altdorf magister, much to their chagrin.
-Mine of The Bearded Skulls: Complex built into one of the tallest peaks of the Spine. It's filled with carvings of bearded skulls indeed. No one is sure wether long lost dwarves or something else built it.
-The Fire Bogs: Another creation by Mazda, he made them to preserve the territory around sunken Chupayotl. Every now and then the broken magic in there does burst out with great gusts of flame. The lizarmdmen don't visit because it is a pinful memory.
-The Sky Roads: Enormous obsidian pathways suspended from towering pillars. They used to connect the sites in southern Lustria like Oyxl and Chupayotl, But big chunks have fallen into disrepair.
-Sentinel of Time: Literally a person frozen in time (human or elf, unclear), not petrified literally just paralyzed for eternity, overlooking the Culchan Plains. Anyone who steps into the plataform the sentinel stands on becomes the new sentinal.