Nazi Germany coveted the prosperous nation of Switzerland and made plans to invade it. But Operation Tannenbaum remained forever a hypothetical exercise and the Swiss were largely spared from the ravages of World War II.
This was in part because the Swiss made thoughtful and thorough plans to defend their nation to the death. Though the Axis powers surrounded Switzerland for almost 5 tears, a German conquest of that nation would be costly--ultimately too costly for Hitler to risk.
Some of the fortifications that the Swiss built to defend their borders include a 10 kilometer stretch of concrete anti-tank barriers near Lake Geneva. These pillars are called "Dragon's Teeth," but people have since come to refer to the remains of this defensive line as the Toblerone Line. That's because they closely resemble Toblerone, the famous Swiss chocolate candy.
-via Atlas Obscura
The Toblerone Line, A Fortification in Switzerland