As a Chicago resident and Architecture fan, I love these three... as a fan of build techniques, man - 21000 and 21001 are some of the worst sets I've put together. : r/lego
LEGO 21001 John Hancock Center Set Parts Inventory and Instructions - LEGO Reference Guide
LEGO 21001 John Hancock Center Instructions, Architecture
LEGO 21001 Architecture John Hancock Center - 100% complete w/ box & manual 673419113281 | eBay
LEGO LEGO ARCHITECTURE: John Hancock Center (21001) New Sealed 673419113281 | eBay
Amazon.com: LEGO Architecture John Hancock Center (21001) : Toys & Games
LEGO Architecture John Hancock Center (21001) Brand New and Sealed 673419113281 | eBay
BrickLink - Set 21001-1 : LEGO John Hancock Center [Architecture] - BrickLink Reference Catalog
LEGO 21001 John Hancock Center Set Parts Inventory and Instructions - LEGO Reference Guide