Bill Gates paid $30.8 million for this book 25 years ago—here's why it still inspires him today

In 1994, right before Bill Gates first became the richest person in the world, he splurged on Leonardo da Vinci's "Codex Leicester" for $30.8 million, making it one of the most expensive books ever sold. Here's why the Microsoft co-founder spent so much money on the book, and the wonderful lesson it teaches us.