Where or where to: в/на + case

Russian asks two different questions where English has one: где? (where, location) and куда? (where to, direction). After в and на, the case of the noun shows which one you mean.

• Location, где? → prepositional: Я живу в Москве (I live in Moscow), Книга лежит на полке (The book is on the shelf).
• Direction, куда? → accusative: Я еду в Москву (I'm going to Moscow), Положи книгу на полку (Put the book on the shelf).

Verbs like жить, быть, работать, лежать, висеть ask где?; идти, ехать, положить, поставить, сесть ask куда?. The prepositional usually ends in -е (-ии for nouns in -ия, -и for feminine nouns in -ь). In the accusative only -а/-я changes, to -у/-ю; inanimate masculine nouns, neuter nouns and feminine nouns in -ь keep the dictionary form: в театр, на окно, в Казань.