Zumthor's Serpentine pavilion is highly regarded as the 'in-between' structure that separates the outside world from the enclosed space that is the garden. The pavilion serves as a bridge between nature and the built environment. I interpret threshold to not only be physical but also psychological. All the entrances in the pavilion are essentially what I identify as a physical threshold that brings visitors to enter either the solitary zone (the narrow corridor) or the social zone (the semi-open space with a garden). Near the entrances, where it is still bright from the sun exposure outside, visitors will feel like they are still outside. Meanwhile, in dark areas of the narrow corridor where there are no physical entrances, visitors will go through a contemplative/introspective state and will feel secluded from the outside world. Naturally, rain is an elemental threshold that further separates and encloses the garden. This effect is achieved because of the shape of the projecting pitched roof.