In an era where computer algorithms automate trading at breakneck speeds, a dwindling number of London's metal traders still conduct business in-person by shouting orders across Europe's last so-called open-outcry trading floor. The nearly 150-year-old tradition takes place in a circle, or pit, of red-leather benches -- called the "Ring" -- where the daily global prices of copper, nickel, aluminium and other metals are set at the London Metal Exchange (LME). "All the shouting and screaming that we do here is used by the whole world," says Giles Plumb, a trader at financial services firm StoneX, who has run its copper portfolio for 21 years. IMAGES AND SOUNDBITES