View looking north over the Grand Basin towards the Peace Monument (Louisiana Purchase Monument) at the 1904 World's Fair

2 clues in this photo

1Weathering

Full canopy along the Grand Basin

By 1904 the Grand Basin is lined with full, dense trees. The 1903 photo shows big trees being transplanted.

The questionHow many mature trees were moved, and from where?

2Demolition core

1,500 buildings, almost none left

The panorama runs to the horizon with palaces on every side. The record gives about 1,200 acres and asks where 1,500 buildings' worth of material went.

The questionWhere did all that material go?

Photo: Official Photographic Company · Public domain · via Wikimedia Commons

St. Louis 1904 Case file

Same kind of clue, elsewhere

#6Demolition core · San Francisco 1915A steel cage under an intact domeIf grand civic buildings had steel and brick cores, what did the fair palaces have inside?

Weathering · Philadelphia 1876Dark streaks on the surviving corniceHow long does weathering like this take, and does any of it predate 1876?

Weathering · Chicago 1893Mature trees on a former swampHow do you get a mature woodland on a swamp in two years?

Weathering · Chicago 1893An established lawn and potted palmsWas the ground freshly made, or already settled?

Weathering · Nashville 1897A weathered grotto overgrown with vinesHow does a grotto look this overgrown at a fair that had just opened?

Weathering · Omaha 1898Young, thin trees: a contrary detailIf the planting was new, was the ground new too, or was an older site cleared and replanted?

All clues others missed →