Bohr’s principle of complementarity predicts that in a welcher Weg (“which-way”) experiment, obtaining fully visible interference pattern should lead to the destruction of the path knowledge. Here we report a failure for this prediction in an optical interferometry experiment. Coherent laser light is passed through a dual pinhole and allowed to go through a converging lens, which forms well-resolved images of the respective pinholes, providing complete path knowledge. A series of thin wires are then placed at previously measured positions corresponding to the dark fringes of the interference pattern upstream of the lens. No reduction in the resolution and total radiant flux of either image is found in direct disagreement with the predictions of the principle of complementarity. The theory of measurement and non-perturbative techniques are aslo briefly discussed.