Crytek Sponza model from McGuire Computer Graphics Archive. Ported to s&box (Source 2).

[Source] https://github.com/edisonlee55/sbox-classic-sponza

[License] Crytek Sponza (CC BY 3.0) © 2010 Frank Meinl, Crytek Link: https://casual-effects.com/data/