Imagine you're playing with toy cars and you create a road that goes up a very big hill. That hill is very steep and it's hard for your toy cars to get up. That road is called Shipka Pass.
In real life, Shipka Pass is a real road that goes through the Balkan Mountains in Bulgaria. The people in Bulgaria have been using Shipka Pass for a very long time - over 2,000 years! At first, it was just a path for people to walk on, but then they started using animals like donkeys and horses to carry things up and down the hill.
Eventually, people started making cars, trucks, and buses that could drive up and down the hill too. But it wasn't easy - Shipka Pass is still a very steep hill and the road is very curvy, which means it goes back and forth a lot. That can be tricky for drivers!
So, to make it easier for everyone to drive up and down Shipka Pass, they built a new road with really cool tunnels and bridges. These tunnels and bridges help cars, trucks, and buses get up and down the hill much faster and safer than they could before.
Today, people still use Shipka Pass to travel through the Balkan Mountains and see all the beautiful scenery. But now they can do it more easily and quickly, thanks to the new road with tunnels and bridges.