The prefix pra-, when used with verbs of movement, means a direction past something.

praeiti - to go/walk past smth
prabėgti - to run past smth
pravažiuoti - to go (by a transport) past smth
praskristi - to fly past smth
prajoti - to ride past smth
praplaukti - to swim past smth

Aš praeinu mokyklą. I walk past the school.
Aš praeinu pro mokyklą. I walk past the school.
Brolis prabėga namus. Brother runs past home.
Brolis prabėga pro namus. Brother runs past home.
Laivas praplaukia miestą. The ship swims past the city.
Laivas praplaukia pro miestą. The ship swims past the city.
Arkliai prajoja kaimą. The horses ride past the town.
Arkliai prajoja pro kaimą. The horses ride past the town.
Paukštis praskrenda Latviją. The birds fly past Latvia.
Paukštis praskrenda pro Latviją. The birds fly past Latvia.
Greitas autobusas pravažiuoja stotelę. A fast bus drives past the bus-stop.
Greitas autobusas pravažiuoja pro stotelę. A fast bus drives past the bus-stop.

Since both have the same meaning, the preposition pro serves only as emphasis when used together with prefix pro-.