 San Lorenzo Colossal Head 1 ( also known as San Lorenzo Monument 1 ) was lying facing upwards when excavated . The erosion of a path passing on top of the monument uncovered its eye and led to the discovery of the Olmec site . Colossal Head 1 is 2 @.@ 84 metres ( 9 @.@ 3 ft ) high ; it measures 2 @.@ 11 metres ( 6 @.@ 9 ft ) wide and it weighs 25 @.@ 3 tons . The monument was discovered partially buried at the edge of a gully by Matthew Stirling in 1945 . When discovered it was lying on its back , looking upwards . It was associated with a large number of broken ceramic vessels and figurines . The majority of these ceramic remains have been dated to between 800 and 400 BC ; some pieces have been dated to the Villa Alta phase ( Late Classic period , 800 – 1000 AD ) . The headdress possesses a plain band that is tied at the back of the head . The upper portion of the headdress is decorated with a U @-@ shaped motif . This element descends across the front of the headdress , terminating on the forehead . On the front portion it is decorated with five semicircular motifs . The scalp piece does not meet the horizontal band , leaving a space between the two pieces . On each side of the face a strap descends from the headdress and passes in front of the ear . The forehead is wrinkled in a frown . The lips are slightly parted without revealing the teeth . The cheeks are pronounced and the ears are particularly well executed . The face is slightly asymmetric , which may be due to error on the part of the sculptors or may accurately reflect the physical features of the portrait 's subject . The head has been moved to the Museo de Antropología de Xalapa ( " Anthropological Museum of Xalapa " ) . 
