Revelation 11:3-12 records a vision given to John, the author, of two witnesses who will appear on the earth during the Tribulation Period. These two individuals will be given supernatural powers, and even though they will be killed, they will rise from the dead and be called back up to heaven. This is one part of the Book of Revelation that can be taken literally, as opposed to other parts that are symbolic, and it will happen for all of the world to witness on the nightly news.
However, as dramatic as all of this will be, what is the point of the passage? Some Bible prophecy experts believe that these two witnesses will be Moses and Elijah returning to earth in literal and physical form. If this is true will it prove to the world, in the end times scenario, that there is life after death? Of course, there will always be doubters or ways people will "justify or rationalize" this away, but what do YOU think? You decide.
God will go to any length to draw people to the truth in the last days.