“In a country like Denmark, where salaries are high, using waste materials usually ends up with the final product costing substantially more than one made from traditional materials,” reveals architect Jeppe Utzon.  Photo 8 of 14 in This Cute Wooden Shelter Is Like an Apartment Building for Bees

This Cute Wooden Shelter Is Like an Apartment Building for Bees

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Mason bees are named for their habit of using mud or other "masonry" products in constructing their nests, which are made in naturally occurring gaps such as between cracks in stones or other small dark cavities.