Shiva (/ˈʃivə/; Sanskrit: Śiva, meaning "The Auspicious One"), also known as Mahadeva ("Great God"), is a popular Hindu deity. Shiva is regarded as one of the primary forms of God. He is the Supreme God within Shaivism, one of the three most influential denominations in contemporary Hinduism. He is one of the five primary forms of God in the Smarta tradition, and "the Destroyer" or "the Transformer" among the Trimurti, the Hindu Trinity of the primary aspects of the divine.
At the highest level, Shiva is regarded limitless, transcendent, unchanging and formless. Shiva also has many benevolent and fearsome forms. In benevolent aspects, he is depicted as an omniscient Yogi who lives an ascetic life on Mount Kailash, as well as a householder with wife Parvati and his two children, Ganesha and Kartikeya and in fierce aspects, he is often depicted slaying demons. Shiva is also regarded as the patron god of yoga and arts.
The main iconographical attributes of Shiva are the third eye on his forehead, the snake Vasuki around his neck, the crescent moon adorning, the holy river Ganga flowing from his matted hair, the trishula as his weapon and the damaru as his instrument. Shiva is usually worshiped in the aniconic form of Lingam. (Wikipedia)
Shiva (also Siva meaning "Auspicious one"), is a major Hindu deity, and one aspect of Trimurti.
In the Shaiva tradition of Hinduism, Shiva is seen as the Supreme Being. In the Smarta tradition, he is regarded as one of the five primary forms of God.
Shiva is usually worshipped in the abstract form of Shiva linga. In images, he is generally represented as immersed in deep meditation or dancing the Tandava upon Maya, the demon of ignorance in his manifestation of Nataraja, the lord of the dance.
Attributes: Matted hair, Crescent moon, Sacred Ganga, Third eye, Blue throat, Ashes, Tiger skin, Serpents, Trident, Drum ---
Shiva meditating in the Himalayan forest
Image source: www.sanatansociety.com

#1: Shiva: A statue in Bangalore, India depicting Shiva meditating
Image source: en.wikipedia.org

#2: A statue of Shiva on Delhi-Gurgaon Highway
Image source: en.wikipedia.org

#3: Shiva and Parvati
Shiva is depicted three-eyed, with a crescent moon on his head, the Ganga flowing through his matted hair, wearing ornaments of serpents and a skull necklace, and covered in ashes, and Trisula and Damaru are seen in the background
Image source: en.wikipedia.org

Image source: www.flickr.com
Reference: en.wikipedia.org: Shiva dancing as Nataraja

#10: Decent-Ganga: Shiva bearing the descent of the Ganges
Image source: commons.wikimedia.org

#19: Shiva protects Markendeya from the god of Death, Yama
Image source: photobucket.com
Click here fot additional image
Image source: Photobucket.com

#20: Siva dances the ananda tandava, the eternal dance of creation and destruction
Image source: commons.wikimedia.org