Along & through

The preposition along is used with nouns like road, river, corridor, line: words that refer to things with a long thin shape.

I saw her running along the road.

His office is along the corridor. To talk about periods or activities, we prefer through.

through the centuries (not along the centuries)

all through the journey (not all along the journey)

right through the meal
Note the special use oi along as an adverb particle in expressions like Come along ( 'Come with me') or walking along (= 'walking on one's way').