You probably need to know this one unless the primary mode of transportation is by car or by camel.
French: Où est le métro?
Spanish: ¿Dónde está el metro?
Arabic: أين هو مترو الانفاق؟
Mandarin: 請問地铁战在哪儿 [Pinyin: Qǐngwèn dìtiězhàn zài nǎ er?] (polite)
English: If you live in America, you don't need to know this one.