"I myself just found out that, in the first Thor movie, the mark of the bifrost is visible for a split second when Odin rips that circle thingy of Thor's chest while casting him out," user Rylact ...
Marvel movies are known for including Easter eggs and hidden nods, but it seems some of them are so deep cut that it takes years for them to be unearthed. This includes one detail from 2011's Thor ...