。
She hung the calendar on the wall.
Literal
She [topic-は] that calendar [object-を] wall [on-に] hung.
~にかける ('hang on / put on') uses に for the surface where something is attached or hung, with 壁にかける ('hang on the wall') the canonical example. かける is a remarkably overloaded verb covering hanging, calling (phone), wearing (glasses), pouring (water on), applying (brakes) — context picks the meaning. Each pairing is essentially a fixed collocation, so memorizing the noun + かける phrases is more practical than memorizing 'kakeru' as a single concept. カレンダー is a common loanword that has fully replaced native equivalents.