The Los Angeles winds its way through the vast metropolis from its headwaters in the San Gabriel and Santa Monica mountains to the ocean in Long Beach. After a particularly bad flooding, the (seasonal) river was encased in concrete by the Army Corps of Engineers starting in 1936, to protect surrounding neighborhoods.

This turned the river into a mere storm drain, a concrete ditch hidden away underneath freeways and bridges, forgotten by most.

In the past decades, beginning with a small band of activists, people in LA have started to get to rediscover their long lost river, and large scale efforts are underway to restore the river to provide recreation areas and wildlife habitats.