A missile has struck the international airport in Riyadh, the capital and heart of Saudi Arabia.

With even a passenger plane hit, major global airlines have successively suspended their flights there.

The culprit behind the attack is none other than Yemen's Houthi rebels.

Who on earth are these people firing missiles at the Middle Eastern powerhouse Saudi Arabia, and why do they persistently target the country?

Now, with even their staunch backer Iran staggering from conflict, what is the real reason the Houthis have drawn their swords instead?

Find out in the video.

(Produced by So Hwan-uk | Edited by Kim In-sun | Design: Cho Eun-sol | Assistance: Kim Chae-hyun | Production: Knowledge Contents IP Team)