Marian and Holy Trinity columns
Marian columns are religious monuments depicting the Virgin Mary on the top, often built in thanksgiving for the ending of a plague (plague columns) or for some other reason. The purpose of the Holy Trinity columns was usually simply to celebrate the church and the faith, though the plague motif could sometimes play its role in their erection as well.
Source: Wikipedia — Marian and Holy Trinity columns (CC BY-SA 4.0)