He taught in Nigeria during the Biafra War.

Entity and relation annotations:
id: 0
type: entity
value: text: during the Biafra War
labels: <Date>
id: 1
type: entity
value: text: the Biafra War
labels: <Event>
id: 2
type: entity
value: text: Nigeria
labels: <Location>
type: relation
to_id: 0
labels: Event:Occurs_on:Date
from_id: 1