All are brothers within the four seas.

四海之内皆兄弟也。

youdao

Within the four seas all men are brothers.

四海之内，皆兄弟也。

youdao

His riches were the possession of all within the four seas.

尊为天子，富有四海之内。

youdao

The Tsunami Early Warning and Mitigation System for the North-eastern Atlantic, the Mediterranean and connected seas is one of four regional Early Warning and Mitigation Systems coordinated by UNESCO- IOC.

UNESCO: Social and Human Sciences

The Tsunami Early Warning System for the North-eastern Atlantic, the Mediterranean and connected seas is one of four regional Early Warning and Mitigation Systems which are coordinated by UNESCO-IOC globally.

UNESCO: Progress Towards a Tsunami Early Warning System in the North-eastern Atlantic, the Mediterranean and connected seas | United Nations Educational, Scientific and Cultural Organization

The Tsunami Early Warning System for the North-eastern Atlantic, the Mediterranean and connected seas is one of four regional Early Warning and Mitigation Systems which are coordinated by the IOC globally.

UNESCO: Social and Human Sciences