1. Until indicates the time of change of an activity or situation.

Pattern 1: verb + until + time
They waited until six o'clock.
The boys studied until midnight.

Pattern 2: verb + until + beginning of event
They lived here until their wedding; then they left.
She was busy until her graduation.
They didn't watch the game until halftime.

Fact
According to Scandinavian folklore, trolls only come out at night because sunlight would turn them to stone.      .. More >>