SIDE A
The second stage: player can look through all of the cards discarded since the beginning of the game (those discarded for coins as well as those discarded at the end of an age), pick one, and build it for free.
Clarification: this special ability takes place at the end of the turn in which this stage is built. If players discard cards this turn (as in the case of the 6th turn of an age), the player can also choose from among them.
SIDE B
The first stage is worth 2 victory points and the player can look at all of the cards discarded since the beginning of the game and build one for free.
The second stage is worth 1 victory point and the player can look at all of the cards discarded since the beginning of the game and build one for free.
When players build the third stage, the player can look at all of the cards discarded since the beginning of the game and build one for free.
Clarification: this special action is taken at the end of the turn in which the stage is built. If players discard cards on that turn (for example, during the 6th turn of an age), the player can also choose from among those cards.