The whole culture & tradition of Sanatan Dharma is designed in a logical & scientific way. Sanatan Dharma has taught for self-realization in order to be complete. But all these knowledge must have a source & it can't be other than the Supreme Brahman or Sadashiva.
On one hand, while Shiva has been described as Formless & the ultimate truth, Shiva can also be perceived through his physical form called as Mahadeva-the dweller of Kailasa mountain. This form itself is the representation of the Ultimate truth. The one thing that makes Shiva unique is that Shiva as the first guru imparted all the form of arts & knowledge to humanity.
Shiva is the originator of tantra-shastras. Tantra is a step by step process to ascend to the divinity. Tantra is a journey from being individual to being everything. Every tantra- Shastra is in form of the conversation between Shiva & Parvati. So Shiva is the first being to give this secret knowledge to the world. Not only to the human but also to demigods & Siddhas.
The characteristics of Shiva as Adiyogi is known to everyone.As the first yogi he imparted the knowledge of yoga to the world. From him, the Siddhas of Himalaya received yoga & developed it as a great science to perceive the completeness.
Shiva is Nataraja. The whole process of Creation & Dissolution can be understood from the cosmic dance of Shiva. Every postures & Mudra during the dance is a great possibility to develop an understanding towards Creation.
Shiva imparted the knowledge of Music to Gandharvas(one kind of semi-divine being connected with music & arts). From Gandharvas, the human beings received this knowledge. Many kinds of musical instruments were designed & the whole of Indian classical music is based on Ragas. Every raga has a deep understanding of nature.
5. War Skill
Shiva himself is a great warrior as Tripurantaka. He is the owner of many war skills as well as many powerful weapons. The Mahabharata is the evidence that Krishna sent Arjuna to Shiva to learn various war skill & Shiva gave Arjuna many weapons.
One form of Shiva is the Rameswaram. The Mercury or Parada is considered very powerful & Parada Shiva Linga has great significance because by the grace of Shiva the Himalayan Siddhas received the knowledge of the ancient science of alchemy.
This is only a glimpse of what Shiva has given to humanity. In reality, the knowledge Shiva has bestowed upon humanity is endless.
(Article contributed by Shri Sourav Bag)