Many people think that Los Angeles is a desert, but it actually is a Mediterranean biome. A Mediterranean biome is defined by 6 months of cool, wet winters, and 6 months of hot, dry summers. Los Angeles was once a thriving habitat to mountain lions and grizzly bears. However, the bears and lions were hunted so aggressively that they went entirely extinct in L.A. Another element in L.A. that has changed over time is the L.A. River. It used to be a prime source of flooding in California. The L.A. River flooded frequently, constantly changing its route. To prevent flooding, architects cemented the majority of the L.A. river. There were also freshwater marshes along the river which would serve as a place to store and convert water, sunlight, and minerals into biomass. Unfortunately, many of California’s marshes have disappeared as a result of human disruption. Currently, some people of the L.A. community are trying to restore the L.A. river’s wetland habitats so it can thrive once again.