"She called it a ball pit for grown-ups," Emi says. The square, one-room house, filled with bursts of color, has an undeniably playful quality about it. Emi, a professional translator in her early ...

London's giant ball pit for adults has had a makeover – all 250,000 balls now glow in the dark. It also has a ball cleaning machine, which can clean 18,000 balls per hour, to make sure the place ...