Although this looks real it's not true according to Snopes,the web site that debunks urban legends.
Read the whole story here.
This idea of encasing a dead body in an air-tight container has been around for a long time. See what follows regarding a very strange but very real patent:
Method of Preserving the Dead
Patent No. 748,284
Inventor: J. Karkowski, Herkimer, New York
Issued: December 29, 1903
The invention relates to certain new and useful improvements in methods of preserving the dead; and it has for its object the provision of a means whereby a corpse may be hermetically incased [sic] within a block of transparent glass, whereby being effectually excluded from the air the corpse will be maintained for an indefinite period in a perfect and lifelike condition, so that it will be prevented from decay and will at all times present a lifelike appearance...
In carrying out my process I first surround the corpse with a layer of sodium silicate or water-glass... after which molten glass is applied to the desired thickness...
I have shown the head only of the corpse as incased within the transparent block of glass, it being at once evident that the head alone may be preserved in this manner, if preferred...