The world is surprisingly small; it is used to express amazement at meeting someone or discovering someone you know in an unlikely place.

दुनिया छोटी है

English Usage: I ran into my old college roommate while vacationing in Greece—it's a small world!

Hindi Usage: ग्रीस में छुट्टियाँ मनाने के दौरान मुझे मेरा पुराना कॉलेज रूममेट मिला - दुनिया छोटी है!