The sanctuary that stood in Jerusalem from roughly 516 BCE until Rome destroyed it in 70 CE — the center of Jewish sacrifice, priesthood, and pilgrimage, whose loss forced Judaism to remake itself around prayer, study, and law rather than a single holy building.
For roughly six centuries, one building was the only site that Jerusalem-centered Judaism recognized as legitimate for sacrifice to God. Then, in the late summer of 70 CE, Roman soldiers burned it to the ground, and it was never rebuilt. Almost everything that Judaism has become since flows from that absence — a religion that learned to survive without the one thing it had been built around.