In what country is the lightning-prone mouth of the Catatumbo River?

Answer 1

Venezuela
On average, the area where the Catatumbo River meets Lake Maracaibo in Venezuela experiences 250 flashes per sq km (0.4 sq mi) per year, occurring on up to 300 days a year. The phenomenon is formally named Catatumbo Lightning, and nicknamed the Maracaibo Beacon.