https://en.wikipedia.org/wiki/Bergius_process
https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...
https://en.wikipedia.org/wiki/Coal_liquefaction
https://en.wikipedia.org/wiki/Synthetic_fuel#History
https://en.wikipedia.org/wiki/Oil_campaign_of_World_War_II
https://en.wikipedia.org/wiki/Gas_to_liquids
Also the reason why France occupied that region of Germany after World War 1, and then hilariously also again after World War 2:
https://en.wikipedia.org/wiki/Saarland
https://en.wikipedia.org/wiki/Territory_of_the_Saar_Basin
https://en.wikipedia.org/wiki/1935_Saar_status_referendum
https://en.wikipedia.org/wiki/Saar_Protectorate
https://en.wikipedia.org/wiki/Bergius_process
https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...
https://en.wikipedia.org/wiki/Coal_liquefaction
https://en.wikipedia.org/wiki/Synthetic_fuel#History
https://en.wikipedia.org/wiki/Oil_campaign_of_World_War_II
https://en.wikipedia.org/wiki/Gas_to_liquids
Also the reason why France occupied that region of Germany after World War 1, and then hilariously also again after World War 2:
https://en.wikipedia.org/wiki/Saarland
https://en.wikipedia.org/wiki/Territory_of_the_Saar_Basin
https://en.wikipedia.org/wiki/1935_Saar_status_referendum
https://en.wikipedia.org/wiki/Saar_Protectorate