City of Ember
(2010)

Lina (Saoirse Ronan), Doon (Harry Treadaway) and Poppy (Amy and Catherine Quin) follow instructions in the box left by the builders and eventually find the way to the surface.

At first they are disappointed because everything is still in dark but in the morning they are awakend by the rising sun.

Again they see the enormous butterfly flying down to the city and they trow a rock with a message down the hole to Ember, where it is found by Loris Harrow, Doon's father (Tim Robins) and thus the path is cleared for others.

Thanks Lukrecija!