Prime Meridian and International Date Line

The International Date Line is an imaginary line on the surface of the Earth that sits mostly on the 180º line of longitude in the middle of the Pacific Ocean. 

The International Date Line lies on the opposite side of the world to the Prime Meridian (The Prime Meridian passes through Greenwich in London.

What is the purpose of the Prime Meridian and International Date Line?

Divides the Earth into Eastern Hemisphere and Western Hemisphere.  The reference for Greenwich Mean Time (GMT) — the global standard for time zones.  Every place east of it is ahead in time; every place west is behind in time.

Prime Meridian = Time Zero (0°) → tells us what TIME it is.

International Date Line = Date Border → tells us what DAY it is.

(Tagalog)

Saan ang hangganan ng Silangan at Kanlurang bahagi ng globo?
Ang hangganan ng Silangan at Kanluran ay ang Prime Meridian at Internationl Date Line. Ang mga bansang nasa kanan ng Prime Meridian, tulad ng Pilipinas, hanggang sa Internatinal Date Line ay nasa silangan (east), at ang mga bansang nasa kaliwa ng Prime Meridian, tulad ng USA, hanggang sa International Date Line ay nasa Kanluran.