I love the photos and history, but have to dispute the bit about second-largest earthwork. Maybe it works under a narrower definition.
Many cities were building landfills in the hundreds of acres in that era, several in the US totaling in the square miles collectively. Some also removed substantial hills. Seattle's
Denny Hill removal was 11 million cy in two phases...the equivalent of 100 acres and 69 feet on average by my calculation.
The building does great things for the skyline.