Step 1: Understanding the Concept:
The Mahabharata, attributed to Sage Vyasa, is the longest epic in world literature. It is fundamentally structured into major divisions known as Parvas. The number 18 holds profound symbolic, structural, and spiritual significance throughout the entire narrative of this "Itihasa" (history).
Step 2: Detailed Explanation:
The Mahabharata consists of approximately 100,000 verses (Shloka-shatasahasri), and the entire narrative is organized into 18 Parvas. These sections cover the history of the Kuru dynasty, from its origins to the final ascension of the Pandavas to heaven.
The 18 Parvas are:
1. Adi Parva: Origins of the characters and the burning of the Khandava forest.
2. Sabha Parva: The assembly hall and the game of dice.
3. Vana Parva: The Pandavas' 12-year exile in the forest.
4. Virata Parva: The final year of exile spent in incognito.
5. Udyoga Parva: Peace negotiations and preparations for war.
6. Bhishma Parva: The first 10 days of war (includes the Bhagavad Gita).
7. Drona Parva: Days 11 to 15 of the war.
8. Karna Parva: Days 16 and 17 of the war.
9. Shalya Parva: The final day of the war.
10. Sauptika Parva: The night attack by Ashwatthama.
11. Stri Parva: The lamentation of the women after the war.
12. Shanti Parva: Bhishma's discourse on Dharma and statecraft.
13. Anushasana Parva: Final instructions on duty and the Vishnu Sahasranama.
14. Ashvamedhika Parva: The royal horse sacrifice.
15. Ashramavasika Parva: Dhritarashtra and Gandhari's retirement to the forest.
16. Mausala Parva: The destruction of the Yadava clan.
17. Mahaprasthanika Parva: The Pandavas' final journey to the Himalayas.
18. Svargarohana Parva: The final ascension to heaven.
Additionally, there is a supplement (Khila) called the Harivamsa, which details the life of Lord Krishna. The number 18 recurs in several other contexts: the Kurukshetra war lasted for 18 days, the Bhagavad Gita has 18 chapters, and 18 Akshauhini (divisions) of troops fought in the battle. This consistency reinforces the text's integrity.
Step 3: Final Answer:
The Mahabharata contains 18 (Ashtadasha) Parvas.