Wall of color

One of the particularly nice things about Austin’s River Walk is that if you catch a boat taxi, you can just sit as it carries you past all sorts of beautiful and photogenic scenery — take this view, for example:

Wall of color

Of course, you’d better have your wits about you.  Things come up fast, and you can miss a number of interesting sights in the time it takes to swap lenses.

King’s Throne

Brought to you from the Natural Bridge Caverns, near San Antonio, Texas — it’s the King’s Throne:

King's Throne

Honestly, I’m not sure where they got the “throne” part of this — looks more like a geological Cthulhu to me. Just the same, it’s an impressive formation.

The Natural Bridge Caverns are in the heart of Texas’ “hill country,” essentially an old limestone plateau since shaped into hilly scrublands by underground erosion and subsequent collapse (much like what happened in the northern Yucatán peninsula). These caverns were formed when the water table lowered, and an eroded underground space gradually was decorated by stalactites and stalagmites formed when water percolated through the surviving limestone overhead, carrying minerals (largely calcite) into their new home.