The King Fahd Causeway is a causeway

Causeway

In modern usage, a causeway is a road or railway elevated, usually across a broad body of water or wetland.- Etymology :When first used, the word appeared in a form such as “causey way” making clear its derivation from the earlier form “causey”. This word seems to have come from the same source by...

 connecting Saudi Arabia

Saudi Arabia

The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...

 and Bahrain

Bahrain

' , officially the Kingdom of Bahrain , is a small island state near the western shores of the Persian Gulf. It is ruled by the Al Khalifa royal family. The population in 2010 stood at 1,214,705, including 235,108 non-nationals. Formerly an emirate, Bahrain was declared a kingdom in 2002.Bahrain is...

. The idea of constructing the causeway was based on improving the links and bonds between Saudi Arabia and Bahrain. Surveying of the maritime began in 1968, and construction began in 1981 and continued until 1986, when it was officially opened to the public.
In 1965, the desire to construct the causeway began to take form officially when Shaikh Khalifah ibn Sulman Al Khalifah

Khalifah ibn Sulman Al Khalifah

‎Prince Khalifa bin Salman Al Khalifa is the Prime Minister of Bahrain since 1971, hence is the longest-serving unelected prime minister in the world...

 of Bahrain paid a courtesy visit to King Faisal

Faisal of Saudi Arabia

Faisal bin Abdul-Aziz Al Saud was King of Saudi Arabia from 1964 to 1975. As king, he is credited with rescuing the country's finances and implementing a policy of modernization and reform, while his main foreign policy themes were pan-Islamic Nationalism, anti-Communism, and pro-Palestinian...

 and the king expressed his wish to have the causeway constructed.