Mertens was born in Neerpelt, Belgium.

Entity and relation annotations:
id: 0
type: entity
value: text: Mertens
labels: <Person>
id: 1
type: entity
value: text: Neerpelt
labels: <Location>
id: 2
type: entity
value: text: Belgium
labels: <Location>
type: relation
to_id: 1
labels: Person:born_in:Location
from_id: 0
type: relation
to_id: 2
labels: Location:located_in:Location
from_id: 1