Pumapunku

C14 dating on the oldest fill layer: construction begun after 536–600 AD, Tiwanaku culture. (Yaeger & Vranich, 2013)

The "H-blocks" follow a common template — a modular standardization, documented by photogrammetry.

Quarries identified by petrography: red sandstone at ~10 km (blocks of 85–131 t for the Plataforma Lítica), andesite at ~90 km on the Copacabana peninsula, crossed by reed raft over Lake Titicaca.

2002 experiment (University of Pennsylvania / Penn Museum): transport of a 9 t andesite block by totora reed raft (1.8 million reeds, 12 t, 15 m) across Lake Titicaca — demonstrating the feasibility of the lake route from the Copacabana peninsula.

Experimental carving by Stella Nair (Protzen & Nair 2013): reproduction of the andesite reliefs with hard stone tools (quartzite, obsidian, jasper, Mohs 6.5–7) and abrasives — refutes the hypothesis of modern or extraterrestrial machining. Protzen achieves flat surfaces to ±1 mm with quartzite abraders.

The abandoned *piedras cansadas* (tired stones) still mark the coast of the Copacabana peninsula and the Taraco peninsula — direct archaeological evidence of an organized lake transport system.

A prepared roadbed (successive layers of soil, gravel, clay) discovered under one of the Plataforma Lítica blocks: the builders prepared the surface to reduce friction during dragging. Lifting method at the scale of the 131 t blocks not demonstrated experimentally — an open question.