This is the 14824th most frequent Russian word.
побережью
"Побережью" means "to the coast" or "to the shoreline" in English.
In this sentence, 'побережью' is in the dative case, used to indicate motion along or across the coast.
Мы гуляли по побережью весь день.
We walked along the coast all day.
Here, 'побережья' is in the genitive case, used as part of a prepositional phrase indicating origin or place.
С побережья открывается великолепный вид на море.
A magnificent view of the sea opens up from the coast.
'Побережьем' is in the instrumental case in this sentence, used to describe the means or area where the action occurs.