When the colossal Mall of America was constructed in 1992, spanning 5.6 million square feet, it skirted tradition – there are no central heating systems within its walls. According to a report by City of Bloomington, the building harnesses the warmth generated by the 32 million people who throng its corridors annually, complemented by heat from lighting and over one mile of skylight coverage to maintain a pleasant 65-to-70-degree temperature range throughout its vast expanse.