Suddenly in Venezuela there was only darkness and the sound of the wind rustling through palm trees. This was Gran Roque, the tiny main settlement of Los Roques national park in Venezuela, a mangrove (a tree or shrub that grows in muddy, chiefly tropical coastal swamps that are inundated at high tide.) Sand that lies less than 100 miles north of Caracas in the Caribbean Sea. It was a weekday night in the middle of winter, at the start of one of the blackouts that has plagued the mainland and these islands for months.