Is this a run-on sentence?
First completed in 1939, the Potomac Park Levee System was installed to protect the National Mall and surrounding areas in Washington, D.C., from flooding.
A: no
B: yes
This is not a run-on sentence. It is not formed from two sentences that have been run together without appropriate punctuation.
First completed in 1939, the Potomac Park Levee System was installed to protect the National Mall and surrounding areas in Washington, D.C., from flooding.