How did the Qin Dynasty unify an empire?

Also in this case

1. 1

   Inscription from Mount Yi

2. TOPIC

   Building the Great Wall

3. TOPIC

   Inside the First Emperor’s tomb

4. TOPIC

   How did the Qin Dynasty unify an empire?

5. TOPIC

   Why didn’t the Qin Dynasty last?

6. TOPIC

   Retracing the First Emperor’s steps today