An inattentive driver could easily miss the flags and road signs that mark the border with Germany on the road leading into the small Danish town of Krusaa.
And that's how the architects of the European Union wanted it: travelers should be able to cross borders within the bloc's passport-free zone with a minimum of fuss and hassle.
Now Denmark is preparing to take a small, but symbolic step away from the vision of a borderless Europe. On Friday Danish lawmakers will vote on a plan to re-establish permanent customs checkpoints in Krusaa and other border crossings; it's expected to pass despite objections from the leftwing opposition.
The government says the plan, designed to stop illegal migrants and drugs from entering Denmark, doesn't violate EU agreements on the free movement of people and goods inside the so-called Schengen zone of passport-free travel. But it's been sharply criticized by Denmark's neighbors, and the EU head office in Brussels, who worry that it sends the wrong signal at a time when European nations bicker over both borders and currency.
"Freedom of travel in Europe is an achievement that absolutely must not be called into question," German Foreign Minister Guido Westerwelle told his Danish counterpart, Lene Espersen, in Berlin. He insisted the new customs regime "must correspond not just to the letter but also the spirit of the Schengen agreement."
The president of the European Commission, Jose Manuel Barroso, questioned whether the Danish plan "would be in line with Denmark's obligations under European and international law."
The proposal comes amid growing doubts in Europe over the Schengen system, which some say has made it too easy for criminals and illegal migrants to hop borders.
An influx of North African immigrants earlier this year led to a border dispute between Italy and France. The French worried the thousands of illegal migrants arriving in Italy would take advantage of the Schengen system to enter France.
Both countries called for reforms to Schengen that would permit border controls in emergency situations, and EU leaders last week approved the creation of new rules to make the use of national border controls within the bloc "a very last resort."
Denmark insists its plan deals only with customs and not passport checks. It calls for "new visible control facilities" manned "round-the-clock" but is vague on details. Speed limits will be lowered and new technology installed to read the license plates of passing vehicles.
Danish Immigration Minister Soeren Pind said the plan entails "permanent" structures at border crossings and adding 98 customs officers to the 142 who already are conducting spot checks.
"But it won't be a control where you take up every person who comes in," Pind told The Associated Press. He dismissed the criticism against the initiative, saying it had been widely misunderstood: "It's much ado about nothing, frankly speaking."
An estimated 17.8 million vehicles cross the 42-mile (67-kilometer) border between Germany and Denmark every year, according to the Danish Road Directorate. Those who live near the border, and regularly cross it for work, social calls or to shop are skeptical about new customs checks.
"I think this is nonsense," said Heidi Schumacher, a 44-year old legal secretary in the Danish border town of Aabenraa. She feared the customs checks would lead to delays and discourage people from crossing the border. "They will not do it if it means they'd have to stand in line at the border crossing."
Espersen, the Danish foreign minister, toured Germany and Sweden to explain the plan, insisting it wasn't about placing an "iron ring" around Denmark.
But Denmark's neighbors remain skeptical, mainly because of how the plan came into being. In essence it's a watered-down version of a much more rigid border regime proposed by the staunchly nationalist, anti-immigration and EU-skeptical Danish People's Party, whose backing is essential for the minority center-right government.
The nationalists used the border control issue as a bargaining chip when the government needed support for its welfare reforms including an overhaul of Denmark's pension system.
"We would like to have gone further," said Soeren Espersen, foreign policy spokesman for the Danish People's Party. "We would like to have gone back to the old border control when people had to show a passport when they had to come into the country, and face the customs when they went in or when they went out."