Steven Spielberg and George Lucas have acknowledged that the rolling-boulder booby trap in the opening scene of Raiders of the Lost Ark was inspired by the 1954 Carl Barks Uncle Scrooge adventure "The Seven Cities of Cibola" (Uncle Scrooge #7). Lucas and Spielberg have also said that some of Barks' stories about space travel and the depiction of aliens had an influence on them. Lucas wrote the foreword to the 1982 Uncle Scrooge McDuck: His Life and Times. In it he calls Barks' stories "cinematic" and "a priceless part of our literary heritage".
StEVen SpiElBerg and georGe lucas HAve aCknOwlEDGed that the rollInG-bOulDEr booby trAp in the opening sCenE OF rAiders Of the lost ark Was iNspIred by The 1954 carl barks uncle scroogE AdVEnturE "tHe seveN Cities of ciBola" (uNclE SCroOGe #7) lucas and spIelbErg HaVe alSo SaiD thaT SoME Of bArKs' sToRieS ABout space trAveL AnD The DepiCtioN oF aLiens hAd an InFlUENCE on Them lucaS wRote THe foRewoRD to tHE 1982 uncLE scroogE mCduCk hIs Life And tImes iN it he calls baRkS' storiES "cinEMaTIC" And "a PricElEsS ParT Of ouR lIterary heRitagE"