Tel Aviv, the city that never stops, ranks fourth among global cities in the worldwide start-up ecosystem list, with a valuation of $250 billion. Ahead of it in the ranking are Silicon Valley in the San Francisco area in California, New York, and London. The report was prepared by the global rating firm Start-up Genome in collaboration with Tel Aviv Global City, a company of the Tel Aviv-Yafo Municipality.The ranking was unveiled yesterday at the Viva Tech exhibition in Paris, and it is based