Sandbox Wonders 3

Trying to come up with places that would evoke wonder in players exploring a fantasy sandbox.  Onward:

23. Tidal Sands - This section of desert acts like waters in a bay, receding to reveal hidden treasures, returning to catch the uncautious in smothering dunes.
24. Calving Cliffs - Rough cliffs above the sea.  They are lined with cairns along their edge (like the tomb of the eagles).  Every so often chunks of the cliff will break away and . . . float.  These floating islands sometimes calve with whole cairns on them, sometimes with a party of tomb looters stuck on them.
25. The Plug - A great lump of lead the size of a keep.  Rumored to have been created to encase a powerful evil.  Constantly hacked at by the poor and greedy-- the lead used to make shot for slings, roofing, pipes - each time some is taken away there is a chance of evil being released to wreak havoc (maybe something like vulture-headed pygmies appear, or worse depending on the amount of lead hacked off). 
26. Tar Glacier - I think just seeing a huge swath of tar filling an alpine valley, infinitesimally creeping forward would be trippy.  What other uses it might have I'm not sure.  (Leave your ideas below).
27. The Fickle River - Every few days this river will completely change the direction it flows.  Commerce and the towns and villages that line it are shaped by this, with different trade and small festivals happening when the current turns their way or remains their way for more than certain amounts of time.
28. Flower Trail Steppes - About a half hour after walking on the ground in this region small, bright flowers bloom all around the area walked on.  Impossible to cross without leaving a colorful trail.  Very dangerous, as bandits and large predators have learned to use this in tracking prey.  The cut sod is worth its weight in gold to potentates for use in gardens.
29. Old Chalk Hills - Rolling hills made up of powdery, grey chalk under a thin layer of grasses. This chalk preserves the life of anything buried in it.  Digging in the hills will uncover every type of ancient life, even humans, which, after catching a few deep, coughing breaths, will resume life.
30. Heavy Sands - These sand bars in a river delta fluctuate in color depending on the health of the ruler of the empire.  The grains act normally-- filling spaces, able to be made into glass-- but are as heavy as lead.
31. The Whirlwind - This persistent tornado is given different names by different cutures- Kasirga, Kimbunga- and is said to have a personality.  It moves randomly across the plains often just in sight, a deadly threat if it decides to come toward the viewer.
32. The Shy Sea - A vast plain of gravel, every few weeks a murmuring sound all around signals the rise of clear, fresh water bubbling up from below.  The waters of this new shallow sea, eventually about as deep as a human is tall, are said to have healing properties.