The following story contains a lot of interesting information. It was originally published in 1838, on the newspaper's 100th anniversary.
There was a vacant lot where the Courier-Post building now stands and the public market house stood in the middle of the street in front of it. (In 1938 the Courier Post was located on the north-west corner of Third street and Broadway)
From Broadway and Third Street to the Hannibal and St. Joseph (now the Burlington) railroad tracks there was a pond.
The site of the present Union station was a sunken piece of land.
These were some of the scenes of Hannibal in the days preceding and during the civil war as remembered by Charles F. Armstrong, 110 Richmond street, retired railroader and grocer and prominent resident of the west side.
To read the story in its entirety, see the Courier-Post website, hannibal.net