The pillar erected by Asoka at Lumbini marked his visit to the place which is associated with which of the following in reference to Buddha?

The Buddha's birth

Buddhist texts make reference to various chaityas and also provide details about locations associated with pivotal events in the Buddha's life. Notably, these include his birthplace (Lumbini), the site of his enlightenment (Bodh Gaya), the location where he delivered his first sermon (Sarnath), and the place of his final attainment, nibbana (Kusinagara). Over time, each of these sites gained recognition as sacred. An example of this recognition comes from around 200 years after the Buddha's time, when Asoka installed a pillar at Lumbini, signifying his own visit to the place.