In October 28, 1943 The 
The U.S. Navy destroyer USS Eldridge (DE-173) went through an extra ordinary scientific experiment (as alleged by some authors). The ship got vanished !. The story claims that the ship have been rendered invisible to human eyes. The name of the experiment comes from the place where the experiment was held at the Philadelphia Naval Shipyard in Philadelphia, Pennsylvania.

The story claims that the U.S. military forces conducted this experiment using an enormous electromagnetic field that turned the whole ship invisible for the eyes. That wasn't even the weirdest part of the story, the fun begins when the ship was found back in another place near New York some days later with many sailors dead while the remaining living sailors went mad for some unknown reason. Some of these sailors were fused to the body of the ship while some other parts of the ship were melt down or re-arranged in strange shapes. 

The story first appeared in 1955, in letters of unknown origin sent to a writer and astronomer, Morris K. Jessup. It is widely understood to be a hoax. The U.S. Navy maintains that no such experiment was ever conducted, that the alleged details of the story contradict well-established facts about USS Eldridge, and that the claims do not conform to known physical laws.

The experiment was allegedly based on an aspect of some unified field theory, a term coined by Albert Einstein to describe a class of potential theories; such theories would aim to describe — mathematically and physically — the interrelated nature of the forces that comprise electromagnetic radiation and gravity, in other words, uniting the fields of electromagnetism and gravity into a single field.

According to some accounts, unspecified "researchers" thought that some version of this field would enable using large electrical generators to bend light around an object via refraction, so that the object became completely invisible. The Navy regarded this of military value and it sponsored the experiment.

Another unattributed version of the story proposes that researchers were preparing magnetic and gravitational measurements of the seafloor to detect anomalies, supposedly based on Einstein's attempts to understand gravity. In this version, there were also related secret experiments in Nazi Germany to find anti-gravity, allegedly led by Hans Kammler.

True Or Hoax? 

We don't know and we might not ever know if the story really happened and maybe the only way to make sure of the possibility of such experiment is to see hidden military objects in the sky or even hidden soldiers but what we may be sure about is as the experiment was never conducted again it may have been a great failure and even the most advanced military technologies for hiding military air crafts use much simpler techniques than what was mentioned in the experiment for avoiding radar detection or being targeted by enemy forces. Yet the experiment may give us some inspiration about the possibility of teleportation or even time travel.