Saddam Hussein: Elusive and rarely seen in public
As US forces close in on the Iraqi capital and make incursions, secrecy still surrounds the whereabouts of President Saddam Hussein, who is reputed to have refuges throughout Iraq.
One of them is an underground shelter in the capital Baghdad which - according to its German architect - is capable of withstanding giant US "bunker-buster" bombs.
The bunker lies beneath one of Saddam Hussein's presidential palaces in Baghdad and "can only be cracked by ground troops or a tactical nuclear bomb", Karl Esser earlier told news agencies.
"Ground troops could get in by taking out the doors with bazookas and explosives", he said.
It's not a combat bunker, it's an air raid shelter, otherwise it would have had to be built with gun slits and a variety of other features
The underground complex - with a steel-reinforced roof and three-ton steel doors - is believed to have been built near the Tigris river in the early 1980s at a cost of about $60m.
It was designed to withstand a nuclear blast as powerful as the one used on the Japanese city of Hiroshima 200 metres (165 ft) away, and also to survive temperatures of 300 C (570 F).
However it is not known whether the Iraqi leader - who assumed power in 1979 - is using the bunker, which is said to be about 30 metres (yards) below ground level.
Correspondents say Saddam Hussein has feared attempts to kill him for years and has hidden bunkers and underground tunnels scattered throughout Iraq.
Construction began in 1982 and Mr Esser said he planned most of the bunker, arranging delivery of equipment such as the air and power supply systems and the doors.
1,800 sq m
Walls up to 2m (yds) thick
3-ton steel doors
Accommodates about 50
Has two escape tunnels
Mr Esser, who had been designing secure shelters for civil defence projects in Munich when he was approached about the Iraqi bunker, said he did not supervise the actual construction and never saw the finished shelter.
However he did go to Baghdad in 1984 to brief officials on technical aspects, and during his visit met Saddam Hussein.
The underground complex's facilities are said to include children's rooms, guards' quarters and a kitchen with 12 months' supply of freeze-dried food, as well as luxury extras reportedly including gold light switches and a spa bath.
The contract came at a time when western firms were legally supplying Iraq with arms and equipment.
Bunker-busters: "Unable to crack Saddam's shelter"
The US attempted to kill the Iraqi leader on the first night of the war, by bombing a compound in southern Baghdad where he was believed to be.
Since then, Saddam Hussein has appeared several times on television.
US officials said "bunker-busters" - GBU-28 bombs weighing 2,086kg (4,600lbs) - were used for the first time in Baghdad on 28 March, targeting a communications centre in the city centre.
The bombs, which are air-launched and laser-guided, were developed for the 1991 Gulf War to penetrate hardened Iraqi command centres.