Sarnath marks the spot of the Buddha's first teaching, and the site's own physical history is largely a record of destruction followed by careful digging back out.
The first turning of the wheel
Buddhist tradition holds that after his enlightenment at Bodh Gaya, the Buddha travelled to Sarnath's deer park and delivered his first sermon to five former companions, an event known as the turning of the wheel of dharma, setting out teachings including the Four Noble Truths. The massive Dhamek Stupa, largely dating in its current form to the Gupta period though built over earlier structures, marks the traditional site of that sermon.
Destroyed, then recovered
Sarnath's monasteries functioned for well over a millennium before suffering severe destruction associated with Turkic military campaigns in northern India around the twelfth century, after which the site was largely abandoned and its structures stripped for building material by later inhabitants. Systematic excavation began under British archaeologist Alexander Cunningham in the nineteenth century, uncovering the stupa remains, monastery foundations and the Ashokan pillar in stages across subsequent decades.
What the digging found
Excavations recovered the broken Ashokan pillar and its now-famous lion capital, along with extensive monastery ruins and sculpture, allowing archaeologists to reconstruct a site whose scale had been almost entirely hidden beneath centuries of accumulated debris and agricultural use before recovery work began.