The ancient temple of Apollo Epicurius at Bassae in the Peleponnese in Greece is a unique world heritage monument. The limestone used however is very susceptible to the elements (ice, rain, acid rain). Currently the temple is protected by a canopy. A case study has been made to build a glass pavilion around the temple. This needs to meet some very strict criteria. First it needs to be as invisible as possible. Secondly as columns cannot be placed inside of the monument glass beams with a 24 m span are required. Lastly the climate inside has to be kept comfortable, preferably using passive systems only.