Description:

A maze of tunnels and mine shafts are all that remains of Sun-River. Chiseled out of the red stone badlands by the water that once ran through it, the location is ultimately abandoned due to the lack of maintenance on the tunnels. It is currently unknown how many branches veer away from the main passage. However, it is abundant in underground flora and fauna because of the clay-rich stone's ability for water retention.

Landmarks:

• Tumbleweed City - A joking name for the small tumbleweed field just outside of the Mines. There's an, honestly irresponsible, amount of tumbleweeds there. Coming to the location from this direction makes it easier to hunt down the mine entrance properly during the day.
• Prospector's Arch - Near the mouth of the main tunnel in, there is a roughly carved stone arch, decorated with names etched into every available surface. It is tradition to place your name on the arch should you leave with a piece of gold or other object found within the mine that you didn't bring in yourself.
• The Gilded Riverbed - The main tunnel that runs through the whole length of the cave is known as the Gilded Riverbed. This is because of the high concentration of gold and gold dust that had been carried down from the surface after decades of intense panning and mining on the surface. The whole floor glitters when a lantern is passed over it.
• Horticus's Hole - Deep in the recesses of the cave system, near the very end, is the entrance to a sinkhole. Found by a cave diver in the latter ages of the mine's existence after the big final collapse, it's theorized that it is where the river 'ended', as shown by the massive aquifer at the bottom of the sinkhole.
• The Hourglass - You will smell it before you see it. Following the acrid sweet smell, you will be met with odd, flowering plants - the only plants that seem to grow beside the typical brush and tumbleweeds here. A mineral-rich, mini-biome of sorts, there are a few pools of still water - likely just leftovers from the last rainfall - that hold things like pyrite and kaolinite (which lend scents of their own to the already aromatic landmark). Most of the plants linger low to the ground, but the flowers of various purples and red seem to get enough sunlight, so they do not need to grow their stalks as high.
  
  If it's not the scent that you follow, on some nights, when the moon is high and full, it would be the faint glowing. Once you're within the Hourglass, it's difficult to discern where the glowing originated from, but some allege that it's the light from the pools bouncing off of the flowers, or perhaps it's the minerals. Whatever the case, it's an interesting sight to see in the middle of a desert.
  
  The shape of The Hourglass is a newer observation, now that there is the proper technology to view it from above and find it; previously, with how flat the land was, it was difficult to get a concrete idea of it. But, much to scientists' delight, it mimics the shape of an hourglass. The pools of water are part of two slightly bigger basins, and the flora and such surrounding the two are following where the richer clay and dirt are.

Lore:

• The once gold-rich river of the badlands had attracted prospectors from across the world with a promise of undeniable wealth. It was even said that the whole bottom of the riverbed shimmered with flecks of the fallen sun with how rich the gold deposits were. However, after the river had been picked clean and gold-hunters began to take to the mines, the development within the mines began to slow down and cave-ins became more frequent. It was suggested that greed had been getting the better of mankind in everyone's attempts to extract without paying proper respects to the earth. It was also suggested that the cave-ins had been a warning from the gods and it wasn't until the final cave-in that the message had been received loud and clear.
• Cut off from the massive industry that had nearly stripped it dry of resources, the mines now lay as an opportunity for study by adventurous spelunkers and daring-do types of people!
• Some have rumors that the area is blessed by Aga; it's a possible reason for there to be foliage and such out here, but it's most likely due to the rich clay and dirt, and the naturally occurring water. (Where is the water coming from? It certainly hasn't rained for a good second. Perhaps there's something else underneath the Sun-River mines...)

Original location inspiration by DoctorLinnec and jackdawjay
Original location inspiration by AlphaSpice