Anime - Shingeki no Kyojin (Attack on Titan)

One hundred years prior to the beginning of the story, giant humanoid creatures called Titans have forced humanity to retreat into a system of concentric walls known as Wall Maria, Wall Rosé, and Wall Sina . 
Inside these walls, humanity lived in peace for one hundred years, but a sudden attack by a gigantic sixty-meter Titan and a smaller Titan covered in armor plates caused the outermost wall to be breached, forcing mankind to abandon the land between Wall Maria and Wall Rosé, resulting in turmoil and famine.
Little is known about the Titans; giant creatures ranging from 3-15 meters tall, which instinctively attack and devour ordinary humans on sight. However, they apparently do not require meat as sustenance, as they do not prey on other animals, even with the long absence of humans, and apparently gain their energy directly from sunlight. They have hard skin and regenerative abilities, and can only be killed by a deep incision at the base of the neck. This weakness led to the development of the Vertical Maneuvering Equipment, allowing humans to navigate quickly in a three-dimensional space. Although it premits great mobility to a skilled user, it carries a large risk of overtaxing the muscles, requiring extensive physical conditioning and agility.

Here is the trailer 

here is the anime of the week, hope you guys enjoy.