The Cutty Sark's masts are being taken down as part of the first phase of the tea clipper's multi-million pound conservation project.
The Cutty Sark is the world's oldest surviving tea clipper
The 137-year-old ship in Greenwich, south-east London, is getting a £25m makeover that will allow visitors to walk beneath the hull.
The three masts each measure more than 90ft (30m) high and weigh 13 tonnes.
In 2004, conservationists warned the Cutty Sark's iron frame was eroding so fast the ship would have to be closed.
Half of the funding for the £25m project has been guaranteed by the Heritage Lottery Fund.
Over the next two years the ship will also be lifted nearly 10ft (3m) out of its dry dock and a catering and educational centre will be built under the hull.
A spokesperson for the Cutty Sark Trust said: "It's a really momentous time. The masts are a real landmark in Greenwich, and now they are gone.
"The real work can now begin on the haul."
It is hoped the historic tea clipper will be open to the public again in autumn 2008.