Wow, it’s on the top of a lonely hill, it looks quite different from a bit further:

A second church, also dedicated to St Michael, was built of local sandstone in the 14th century by the Abbot Adam of Sodbury, incorporating the foundations of the previous building […] St Michael’s Church survived until the Dissolution of the Monasteries in 1539 when, except for the tower, it was demolished

https://en.wikipedia.org/wiki/Glastonbury_Tor

Very imposing.