Hi,
today I will write about pareidolia a commonly seen phenomena. People often see familiar objects in completely random things, like rocks.
Clearly there is face in the upper middle part of the picture on the left. There is definitely sign of both eyes, of nose and mouth, thats more than one needs to
recognise face in something, consider the following one on the right. Do you see the black thick circle filled with yellow color, two ellipses and curved line extended in the ends? Yeah me too.
The point is that humans are great in recognizing (most often faces) in things that are actually not them. The first picture is photo of region Cydonia which is a area on Mars. It was taken in 1976 by Viking 1 and of course people thought that it was proof for extraterrestrial life! Well if you take enough photos of Mars there is high probability that some of the rocks there will resemble primitive faces.

“I am the evidence of life on Earth, beware!”
Pareidolia does not happen only in images but also in sounds. For example there is a group of people who listen to so-called “ghost boxes” (sub category of ghost hunters). Ghost box is a box that is skimming quickly through radio channels. This creates lot of background noise and static noise with mix of what you can hear from the actual radio.. they say that the ghost can easily communicate through it.
Simplest explanation is of course that they just interpret extremely bad audio as some kind of words, plus if they listen for many hours they will eventually pop out something that will be an answer to your question, here is a link so you can consider for yourself, remember humans are great in interpreting random noise as actual words[1] (skip like 3 minutes for actual talk).
The story of the original Mars picture got stretched over many years. 2 decades after taking the picture, there was much better one taken by Mars Express as you can see below it was just the low resolution of Viking spacecraft.
There are many things that can trick us so it is not best to take the first explanation that we can think of, be sceptical and do not share if you do not know anything about it.
Dragallur
[1]The “answers” should be mostly made by random quotes from songs.
Smiley: By en:User:Mystìc – Originally created by en:User:Mystìc at en:Image:SNive.gif. Vectorized by Psiĥedelisto, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=55079042
Pear: http://www.dailymail.co.uk/femail/article-3280816/What-photos-s-faces-suffer-facial-pareidolia.html