The most documented of GLMZ's Lost Blocks, Linden Block occupies the space between McKenzie Street and Halsted Street in the Circuit District. Satellite imagery shows approximately twelve buildings arranged along two parallel streets — Linden Street and an unnamed cross-street — with what appears to be a small park or green space at the eastern end. The buildings are residential in character: three to four stories, flat-roofed, with windows that show curtains and occasional interior lighting during nighttime satellite passes. Twenty-two confirmed delivery records exist from the period before the block became inaccessible, documenting a functional neighborhood with residents who received packages, signed for deliveries, and lived ordinary lives on streets that now cannot be found.

Linden Block became inaccessible in 2219. Before that year, the alley connecting McKenzie Street to Linden Street was a normal urban passage — delivery drivers used it, residents walked through it, BCI navigation routed through it without incident. At some point during 2219, the alley ceased to exist. No construction was observed. No demolition permits were filed. No noise, no dust, no equipment. The alley was there, and then a continuous brick wall was there, and the wall showed decades of weathering as if it had always been the only thing in that location. Thermal imaging shows approximately 80 heat signatures within the block — the largest concentration of any Lost Block. They move through the space on daily rhythms. They cook. They sleep. They appear to gather in the small park during evening hours. They are unreachable.

The delivery driver Ria Okonkwo-Salazar made seventeen documented deliveries to 4412 Linden Street between 2218 and 2219, the final delivery occurring three weeks before the block became inaccessible. Her delivery records, BCI navigation logs, and signed receipts constitute the most detailed documentation of a Lost Block's interior from the period when it was still accessible. The recipient, a woman named Desta, has not been seen outside the block since 2219. Whether she is among the 80 thermal signatures, and whether she could leave if she wanted to, are questions that nobody can answer from this side of the wall.