The Great Depression
proper noun
世界 means "world" and 恐慌 means "panic" or "scare," so when you put them together you get a scare that made the entire world panic. This is how we refer to The Great Depression. It was caused by and subsequently resulted in everybody in the whole world panicking together about money.
せかいきょうこう
This is a jukugo word that uses the on'yomi readings of the kanji. You've learned them already, so you should be able to read this on your own!
私の祖父は世界恐慌が起きた年に生まれました。
My grandfather was born the year the Great Depression occurred.
世界恐慌は様々な国に影響を与えた。
The Great Depression affected many countries.
世界恐慌は失業率と共に自殺率までも上げた。
The Great Depression raised unemployment and even suicide rates.