Society, The Universe
Both kanji mean world, so it should be easy to guess this is a word for the World. It also means society or the Universe.
This is a jukugo word, which usually means on'yomi readings from the kanji. You know the on'yomi reading for 界, but you didn't learn this on'yomi reading of 世, so here's a mnemonic to help you remember:
What's the most hated vegetable in the world? Celery (せ), probably. The world is divided into those who love celery and those who hate celery. Which one are you?
The world is big, so I want to go to various countries.
This documentary has become a popular masterpiece worldwide.
Many artists have a world of their own.