The number "97" on the water tower and building is advertising the street address of the Fred Lawrence Printing Company at 97 Woodward Avenue. Their street sign is visible in both images. The earlier image doesn't show the number.

The white building half hiding the Hotel Pontchartrain in the original photo is called the Vinton Building. In Doug Floor Plan's photo, it is hidden behind the Z-shaped First National Building. This photo shows the Vinton Building with the First National behind it.

What is with the large 97's on the one building corner as well as the water tower?

Comparing the 1917 view and this 1918 view, two new skyscrapers were built! Is that even possible? The Cadillac Square building at the right (which still exists but lost it's its minarets), and the white building in front of the Hotel Pontchartrain, which is gone. In fact, even this portion of Bates street is gone, it's now under the City-County building and the parking structure behind.

["Circa 1917" doesn't mean "in 1917." It means around ("circa"!) 1917. - Dave]

Three of the four buildings marked with red dots were very prominent in the 1918 Detroit skyline (at left), but now are just faces in the crowd. At the bottom with a red dot is the back of the First National Bank, which replaced the Hotel Pontchartrain (backside is seen in 1918).

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