This allows for an interesting comparison of our lifestyles: B has worked hard his life and now can enjoy his retirement in luxury, but is unable to climb 2 km, which is just warming up for me. I enjoy my life while I'm young, but will spend old age in poverty if I continue this way (or commit suicide once I realize it will only go down financially, physically, psychically).
Along the way, there was a rock slide. The brown spots are crystalline quartz (?) on limestone:
into first cave, which has two holes on the ceiling
and more stalactites and stalagmites and handwriting of Thai kings who visited the cave
these spots on the ground are from dripping water
but I've no idea where these structures come from (looks similar, but smaller, to Phu Hin Rong Kla National Park Phitsanulok)
Finally, nearby Wat Bang Pu วัดบางปู has a roof covered with green glass bottles. That makes 6 bottle temples, the other 5 see here: http://christianpfc.blogspot.com/2015/09/bottle-temple-in-surin-province.html