Workers and other architects were baffled by his plans for the cistern as it included reusing decorative columns taken from temples that were in disrepair as well as creating entirely new decorative columns from materials left from his reworking of the Hagia Sophia. It included exquisite carvings and an area for gardens in places where shafts of light were designed to come down. It needed those shafts for light because the cistern is underground; few people were ever meant to see it (aside from the thousands of slaves who constructed it). The other architects and workers wanted to know why he would put so much detail into something so few people would see.
He answered that beauty should be built into everything. Even those few workers who would check on the cistern deserved beauty in their lives. Today, tourists travel there to see a masterpiece of engineering adorned with such beauty.