Junction means 'place of union' especially 'railway junction'.
Juncture means 'a critical point of time'.
1. Jubbalpore is the railway junction in India.
2. I met him at the junction of Beadon Street and the Mall.
3. There was an accident at the junction of Park Road and School Lane.
1. At this juncture the arrival of Sham Lal saved the situation.
2. At that juncture he had no idea what to do.