I just found two neat pictures that illustrate this challenge very well!!!
These are from a neat pictorial history of the Civil War areas, from the wartime AND the present standpoint.
"The gateway to the cemetery at Gettysburg, Pennsylvania, July 1863. It was built nine years before the battle at Gettysburg, which lasted three days and resulted in 51,000 casualties."...

- EvergreenCemetery-Gettysburg-July1863.JPG (122.38 KiB) Viewed 1055 times
Present-day Evergreen Cemetery at Gettysburg...

It looks to me like this was the gateway as it was being built, and it probably had the building attached to it that is in the next picture, by the time of the Battle of Gettysburg.
Still...it's a good example of an enduring piece of architecture that has had changes made!