Journey into Mystery / Thor Vol 1 #71

Plot

Two newlyweds in Egypt uncover a huge egg in the sand that hatches into the Roc in the warm sunlight. The monstrous bird flies around gathering parts of bridges, trains and other items to use in constructing a nest until the scientist that uncovered the egg gets the idea to build a robotic duplicate that flies into outer space, enticing the Roc to follow it in its forlorn quest for a mate.