It’s the fourth year of Jerusalem’s Light Festival, where visitors can stroll along three different routes through the Old City, gazing upon exhibits large and small, subtle and unpredictable that focus on light — its refraction, reflection, projection and endless creative manipulation.

Each route takes about 30 minutes to walk, and being dazzled earlier in the immediate aftermath of nightfall is better than later, as the crowds tend to grow from 9 p.m., making it more difficult to get a good view.

This year’s favorites include the light cave at the end of the Green Line and the “Spirit Light of the Forest,” the bubble light piece just outside Jaffa Gate where giggling folks of all ages are photographing each other in weird silhouette form. On Greek Orthodox Patriarchate Rd, the Blue Line’s assortment of ghostly projections — a spider’s web, a manic organist, and all manner of other eerie apparitions with suitably startling soundtracks — is seriously discomfiting when encountered by the unprepared.

It also pays to make your way to the end of the White Line, where the light show at the Western Wall shows off the massive stones of the ancient walls in all their glory.

Jerusalem Light Festival, through June 13; entrance is free.