This is a copy of the Canterbury cross, emblem of Salvation and Friendship, mounted on a piece of masonry taken from an external wall of the cathedral. It is believed to date from early Christian Saxon times, becoming an emblem on badges purchased and worn by pilgrims from around 1200 to 1400. An example of the cross was found in 1867 under St George's Street. It also appears in a badge found under Eastbridge Hospital. The badge seems to be unique to Canterbury.
What to see (Image 1):
the cross situated on the north wall of the nave near the south west porch entrance
nearby the list of 93 cathedrals to which copies of the cross have been sent from the Mother church