Buy a legitimate copy of Warcraft III (currently ~$30 USD) or use the free Dota 2 Arcade alternative. Avoid shady "free download" websites – they are either outdated, illegal, or dangerous.

It was IceFrog who polished the game into the balanced, high-skill competitive masterpiece that eventually caught the attention of Valve. For over a decade, Dota 1 reigned supreme in internet cafes from China to Peru, laying the foundation for the modern MOBA genre.

(short for Defense of the Ancients ) is not a standalone video game. It was a custom user-created map for Blizzard Entertainment’s real-time strategy game Warcraft III: Reign of Chaos and its expansion, Warcraft III: The Frozen Throne . Developed by community modders like "Eul," "Guinsoo," and "IceFrog," Dota 1 became the grandfather of the Multiplayer Online Battle Arena (MOBA) genre, inspiring League of Legends , Heroes of Newerth , and Dota 2 .

While the engine is different (Source 2), the

Ensure you have The Frozen Throne expansion installed.