As readers of Marvel Comics know well, Captain America is alive today only due to a freakish miracle. During World War II, he was involved in an accident involving an airplane. He plunged into icy waters where his body was frozen, only to be thawed out many decades later. Or at least, that's the way Stan Lee and Jack Kirby presented it in the comics.
Me, I've always found that story kind of hard to believe. I buy the one about the guy getting transformed into a hulking green monster because of gamma ray bombardment. I believe the one about the kid gaining spider-like powers after being bitten by a radio-active spider. And of course, I believe that Thor, God of Thunder, comes down the rainbow bridge to visit Earth and arrest bank robbers. That's all highly credible. But a World War II combatant frozen in a glacier for all those years? Ridiculous.