The Bermuda Triangle is used as an Ekaterina stronghold. It was mentioned in Beyond the Grave by Alistair that there was an Ekaterina stronghold there. Uranium is a known Clue that was hidden there. It is the perfect place to hide the Clue because it is a very far away place and has many scary rumors, because of the disappearing ships and planes that never come back due to the stronghold's extremely high-tech security system. It is also mentioned that the Ekaterinas keep other branches out of their strongholds by sinking their ships and planes--the explanation for why so many vehicles are destroyed there. For Non-Cahills this placed is believed to be cursed and have an electromagnetic field.
The Bermuda Triangle is featured on Card 211: Bermuda Stronghold.
Card 29: Bermuda Triangle features a sinking Lucian ship in the Bermuda Triangle, which uses flags to code the message "Ekats got us."