In the 1950s, oil exploration in Libya revealed that the country also had huge aquifers lurking underneath its scorching sands. Libyans weighed the costs of bringing water up from the aquifers against transporting water from Europe or the desalination of salt water, and chose the aquifers as the most cost-effective option.
: https://www.cia.gov/library/publications/the-world-factbook/geos/ly.html