Experiment of Alain Aspect, Philippe Grangier, Jean-François Roch et al. showing delayed determination of photon path.
<a href="//commons.wikimedia.org/wiki/User:Patrick_Edwin_Moran" title="User:Patrick Edwin Moran">Patrick Edwin Moran</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>