Saint Thérèse of Lisieux was a French Catholic nun who died in 1897. Loads of people wanted her to be made into a saint.
Now a small casket of some of her bones - called relics - are kept inside a 21-stone silver container.
Her remains which include bones from the right thigh and foot have been touring the world since 1997.
It's so heavy that it took six men to carry the casket inside Lancaster Cathedral.
Saint Thérèse is known to lots of Roman Catholics as the "little flower of Jesus" and loads of people have turned out to see her relics.
The relic has toured more than 40 countries including Australia, America, Iraq and even space.