The Great Archive:

At the start of each session, the owner of the Great Archive may choose to place any tech they have already unlocked into the wonder, to a maximum of four techs at a time. Increase the amount of Research Points this wonder produces and the amount of Wood it consumes by 1 per tech placed into the wonder. When a tech is placed into the wonder, no benefit is gained from its effects until it is released. A tech cannot be released once it is placed inside, and is automatically released after 1d4+1 sessions. Once released, a tech cannot be placed back into the wonder. Additionally, any nation with a defensive pact, military pact or who are the vassals of the wonder owner gain dramatically increased chances of success on all attempts to discount the cost of techs within the wonder. Lastly, the owner of the wonder gains slightly increased chances of success on all attempts to discount tech costs, or gather research points.