We were built by Aliens, just like we build computers and robots. May be we are very sophisticated robots. Just as a computer has a hardware part and a software part, we also have both the parts. Our body is the hardware and our mind is the software (said to be the soul). There is a basic OS, which we humans and other animals also have; it helps us to do simple tasks like walking, sleeping etc. But there is also a very sophisticated software present inside us and not in animals. This software is what differentiates us from other animals on the planet. We can think, imagine, have dreams and do a lot of similar things. These are the things that differentiates us from other animals. And these things are not physical capabilities but mental capabilities and can be done only by the specialised software inside our brain. When this software malfunctions we have mental illness.
People who have near death experience say that they seemed to travel through a dark tunnel which has a bright light at the end of it. This phenomena occurs because our body is configured in such a way that when we die the software inside us (referred to as soul ) goes back to a central database, just like we have cloud storage. This software is again utilized and put into other human beings. The memory part is wiped so that we cannot remember anything from past life. When we do a cloud back up of our PC the data remains there more or less permanently and if our PC breaks down (dies) we can restore the data back into a new PC. So the data never dies. From the ancient times it has been said that the soul never dies, its just because it gets stored and transfered from one person to another. Any ways we cannot kill a software.
If some day we could be able to stop the exodus of the software from our body we will be able to live eternally. There have been many saints in this world who have been able to do this miracle. Now also there are lot of saints in the Himalayas who live in treacherous conditions where normal people would die. They can go without food for long time. Many experiments have been done to see how they can survive. Some can survive without air also for a long time. There is word called Nirvana or Moksha, this is actually a state where we can take control of the software inside us, just like Hacking.