A mother and her son drowned in the murky waters just off Thessaloniki’s landmark White Tower when their car plunged off the esplanade just before dawn yesterday. It was the third incident of its kind in the past 10 days. The bodies of driver Angelos Nannousis, 30, and his 65-year-old mother Georgia, from the village of Alistrati near Serres, were found trapped in the vehicle by port authority divers. It was unclear what caused the car to swerve off the road, near the Macedonia Palace Hotel, and drop off the waterfront at around 5.20 a.m., although initial reports said one of the tires had burst. On April 28, two people died when a car crammed with seven women and children plunged off the waterfront at the village of Vassiliki on the island of Lefkada. And last Friday a man drove into the sea on the outskirts of Thessaloniki, in a death that is being treated as suicide.