Subscribe | UPI Odd Newsletter Subscribe LONDON, Jan. 28 (UPI) -- A realistic "polar bear" seen wandering the streets of London and even riding the city's subway was a high-tech puppet promoting an upcoming TV series. The 8-foot-long beast, which was created and sent to the streets of London to promote Sky Atlantic's new Arctic-based series Fortitude, was built by 19 prop specialists over the course of eight weeks and was operated by two puppeteers inside the bear who practiced for weeks to get a realistic gait, the network revealed. Advertisement The "polar bear" was seen wandering locations including Millennium Bridge and Hampstead Heath. The life-size puppet also took a ride on a London Underground train. "We wanted to bring a realistic polar bear to the streets of London to give people an up-close experience of what it must be like to come face to face with one of the biggest, but uncredited stars of our new show," Sky Atlantic director Zai Bennett said.