In the mid-1990s, the modern wingsuit was developed by Patrick de Gayardon of France, adapted from the model used by John Carta. In 1997, the Bulgarian Sammy Popov designed and built a wingsuit which had a larger wing between the legs and longer wings on the arms. His prototype was developed at Boulder City, Nevada. Testing was conducted in a vertical wind tunnel in Las Vegas at Flyaway Las Vegas. Popov's wingsuit first flew in October 1998 over Jean, Nevada. Popov's design was a great improvement in creating lift; it was able to slow the vertical speed to 30 km/h while gliding horizontally at speeds over 300 km/h.