An Aerial view of Sunken City in San Pedro. In 1929, a sizeable section of land in the southern tip of San Pedro began to unexplainably slip into the sea. The 600 block of Paseo Del Mar began moving seaward in 1929 and continued to slip until the mid 1930s. Movement was measured as high as 11 inches a day. Due to quick action, all but two of the houses on the seaward side of the street were moved before toppling into the sea. The eastern section of Point Fermin Park was lost and the entire area is very unstable, yet not moving at the present time.
Geologists have termed this phenomenon as a "slump" and this area has been featured in many geological studies and books. This geological mystery also occurs about 4 or 5 miles up the coast from this spot at Portuguese Bend in Rancho Palos Verdes. The Portuguese Bend Slide Area is still moving and slipping into the sea.
Palos Verdes Drive South, the main road through the area, has to be refurbished continuously and frequently as it is constantly being displaced by the movement. This area is closed by chain link fencing, but may still be viewed at the south end of Pacific Avenue or the east end of Pt. Fermin Park at Paso Del Mar and Gaffey Street.