Catatumbo Lightning

According to Wikipedia:

The Catatumbo lightning usually develops between the coordinates 8 ° 30 'and 9 º 45' north latitude and 71 º and 73 º W.
The storms (and associated lightning) are likely the result of the winds blowing across the Maracaibo Lake and surrounding swampy plains. These air masses inevitably meet the high mountain ridges of the Andes, the Perijá Mountains (3,750m), and Mérida's Cordillera, enclosing the plain from three sides. The heat and moisture collected across the plains creates electrical charges and, as the air masses are destabilized at the mountain ridges, resulting in almost continual thunderstorm activity[5].
The phenomenon is characterized by almost continuous lightning, mostly within the clouds, which is produced in a large vertical development of clouds that form large electric arcs between 2 and 10 km in height (or more). The lightning tends to start approximately one hour after dusk.
Among the major modern studies there is the one done by Melchor Centeno, who attributes the origin of the thunderstorms to closed wind circulation in the region.
Between 1966 and 1970 the scientist Andrew Zavrostky with assistance from the University of Los Andes made three expeditions which concluded that the area would have several epicentres in the marshes of the Swamp National Park Juan Manuel de Aguas, Claras Aguas Negras and west Lake Maracaibo, and in 1991 he suggested that the phenomenon occurred due to cold and warm air currents meeting around the area. The study also speculated that an isolated cause for the lightning might be the presence of uranium in the bedrock.