In early March 1938, Southern California endured four days of extraordinarily heavy rains that resulted in devastating floods. Consequently, Los Angeles decided to engage the Army Corps of Engineers to pave over the Los Angeles river so that it could be better controlled. These days, it’s such an enduring part of the LA cityscape that it can be hard for us 21st century Angelenos to remember that it once looked like a regular river. This shot of it is circa 1938 and shows us what it looked like when facing north from what was then known as the Ninth St Viaduct, but is now called the Olympic Blvd Viaduct, east of downtown LA. (Source: CurbedLA)
This is roughly how that view looks these days.