Thirty miles to the south lies another scene from the Marie Celeste in an equally drab, 1950s complex outside Mons, close to the Belgian-French border. This is the headquarters of Supreme Headquarters Allied Powers Europe (Shape), the home of General Wesley Clark, the alliance's top general, who is in charge of the Kosovo campaign. Needless to say, Gen Clark is not in his wood-panelled office this weekend, but at Nato's ceremonial gathering in Washington.
The flight of the generals and bureaucrats to the citadel of western politics underlines a central feature of the Balkan crisis. The military may be in day-to-day charge but they are fighting a politicians' war, and a particularly complex one at that.
If Gen Clark has sometimes given the impression that he is working with one hand tied behind his back, it is because the objectives of the Kosovo campaign are set by committee, and not by his high command. Unlike most military leaders, the American general is answerable to 19 nations, each with a different agenda.
The physical separation of Shape and Nato is hardly the extent of his problem. Gen Clark is hundreds of miles from the command centre for his multi-national force of airmen, soldiers and sailors. That unit, Allied Forces Southern Europe (AFSouth), commanded by an American admiral, James Ellis, is in Naples, which is also the headquarters of the air and naval campaigns. Humanitarian and peace implementation forces are in Albania and the Former Yugoslav Republic of Macedonia. Daily contact is through a secure video link.
The general also has a quasi-diplomatic function. He has to keep on good terms with the chiefs of staff of all 19 alliance nations, particularly those providing men and equipment. High on his list is the Chief of the Defence Staff in London, General Sir Charles Guthrie, with whom he speaks regularly.
As the conflict enters its fifth week, the alliance is counting the cost of its co-ordination difficulties, and of the divergent views held by its military and political leaderships. It has also been forced to re-examine its tactics. On the assumption that President Milosevic wanted an excuse to back down, the air campaign began slowly, taking 10 days to build up to the level with which the Gulf War began. Strict guidelines were laid down for targeting, with the politicians anxious that nothing overtly civilian should be hit. When permission was canvassed to target Serbian television, it was denied. Only after weeks of pressure were the military allowed to go ahead on Friday night.
With poor weather adding to Nato's woes, it has had to admit that the air campaign has not destroyed Mr Milosevic's will, let alone curtailed the humanitarian disaster in Kosovo.
Madeleine Albright, the US Secretary of State, has taken much of the criticism for that early misjudgement. But she had good reason to hope that Mr Milosevic would back down. The Nato nations have maintained unity, but their solidarity masks deeper tensions. Several members have acute reservations about the campaign. In Greece, where popular opposition to the bombardment has reached 95 per cent in some polls, the Pasok (socialist) government has refused to supply aircraft and would balk at the idea of aiding a ground invasion. It faces European elections in June and national elections within a year, and knows the war is a losing issue. And Athens believes that the Kosovo Liberation Army's real agenda is for a greater Albania including parts of Greece.
Italy, geographically close to the bombing, is so sensitive it held up an EU oil embargo before relenting last Wednesday. Spain and Portugal made only small deployments and kept low profiles. Even in Germany, doubts about the wisdom of intervention go deep. Joschka Fischer, the German Foreign Minister and Green party leader, has pushed for a diplomatic settlement, stressing the need to maintain contacts with Russia.
His efforts are prompted partly by pressure from inside the Greens, but this determination to keep diplomacy alive reflects a wider alarm among the German public. "In Britain," said one diplomat last week, "your public is used to this kind of military campaign. You have had the Falklands war, the Gulf War. For Germany this is the first military action since 1945. For us, the longer it goes on the more difficult it becomes to explain."
That makes one likely scenario, an intensified bombing campaign over months, an unpalatable one. But the alternative, a ground war, may be worse. On this vexed issue the military planners and the politicians may be moving closer together. Yet this brings to the fore the dilemma of Nato's less bellicose nations; they want the conflict over quickly, but are the most reluctant to risk their soldiers' lives to bring about an early end to the crisis.
The alliance's difficulties presenting its case became clear in the row over the bombing of the refugee convoy, the biggest public relations disaster of the campaign. In the face of what one senior diplomat describes as "a Goebbels-quality propaganda in Belgrade", the alliance has come off second best.
Its failure to admit early on that it had caused civilian casualties gave the Yugoslav government a chance to exploit scepticism about Nato's version of events. Western journalists taken to the scene saw fatalities, some of which Nato now believes were inflicted by Belgrade.
In Brussels, Nato's press spokesman, Jamie Shea, battled in vain to persuade Shape to provide an early explanation, and his embarrassment was compounded when the Pentagon publicly contradicted the Nato version of events. Mr Shea, a Nato official, has limited power to determine what information reaches the public; that decision ultimately rests with Shape.
Five days after the event Nato presented a fuller and more convincing picture, but not before Downing Street had offered to bolster the alliance's over-stretched press operation. Several hours before the press conference on Monday, Tony Blair's chief spokesman, Alastair Campbell, went to Brussels to give behind-the-scenes advice. Meanwhile, one of his deputies, Julian Braithwaite, has been seconded to Nato.
But augmenting the press operation has provoked other tensions. Mr Shea is British and his daily briefing was normally accompanied by a military update from an RAF Air Commodore, David Wilby. With greater Downing Street involvement, Nato's press operation has had to battle accusations of an Anglo-Saxon takeover. As a result, Air Commodore Wilby has taken a back seat to an Italian general, Giuseppe Marani, whose accent has caused consternation among US TV crews.
Waging a real conflict is not as easy as conducting the Cold War for which the alliance was established 50 years ago. Accompanying the universal outrage at Mr Milosevic's tactics is a new respect for his toughness. What is needed, argued one source last week, is a thorough tightening of the operation, linking Nato's bureaucracy to Shape's line of command "to create a political and military structure that speaks with one voice". Only then will the most powerful alliance in history be an effective adversary for Belgrade.