To understand that scripture, you have to read the entire Revelations 11 to get the context of it. In verses 1-6, and angel appears and says that there will be two prophets, who can not be killed by any man. The prophets will have power to cease the rain from falling during the time they are prophesying, to turn waters into blood, and to "smite the earth with all plagues, as often as they will."
In verses 7-10, following the two prophets testimony, Satan makes war against them and kills them. Their bodies shall lie in the street of the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified. What is meant by that is allegorical, because Jerusalem will no longer exist in that time. Therefore it is called "Sodom and Egypt." The scripture does say that people of different languages and nations will see that the prophets are dead, but the scripture doesn't go into detail just how. So you could consider live streaming, or any other method available at the time these things will take place. Nobody really knows at what point in the future these things will happen, so that's all I can tell you.
Verses 11-14 relate how the two dead prophets will be resurrected, which be be a frightful thing to the people. They ascend into heaven and within the hour, there will be a massive earthquake that will destroy a tenth of what was once Jerusalem, killing 7,000 people. The rest of the people will be frightened by that and gave glory to God.
