the.com/travertine
Limestone that grew up watching mineral springs drip — now it's a billionaire's bathroom floor.
slow buildForms when calcite precipitates from hot or cold springs
roman flexThe Colosseum is built largely from it
the holesNatural pits from escaping gas during formation
still growingForms today around active geothermal springs and waterfalls
name originNamed for Tivoli, Italy, ancient Latin Tibur