LONDON (Reuters) - The Aquatics Centre has been dubbed a masterpiece. The Velodrome has drawn gasps too. And tens of thousands of those attending the London Games have caught a glimpse of another unique building on the way - step forward, "The Cathedral of Sewage".

Olympic fans watching Usain Bolt sprint to glory or Michael Phelps take his record-breaking bow are being asked to leave the main venue via Greenway, a renovated pathway taking them away from busy stations towards the West Ham area of east London.

They pass an unusual building behind high barbed wire that few Londoners know much about, let alone the American, Hungarian and Japanese tourists on the path.

Some may recognize it as the Arkham Asylum used in the 2005 film "Batman Begins". But its day job is Abbey Mills Pumping Station, built in 1868 to remove the stench of raw sewage in the Thames and still dealing with the biggest overflow of sewage in London.

Designed in a cruciform plan and heralded as a marvel of Victorian engineering, it was dubbed "The Cathedral of Sewage" or "The Temple of Sewage" and is now proving a mystery to Olympic visitors.

One curious Olympic spectator said she had no idea what it was, but detected "a faint whiff".

(Reporting by Steve Slater; editing by Michael Holden)