The City of Ember by Jeanne DuPrau

The city of ember is a great book about a city surrounded by darkness. The city's people believe that they are the only light in the dark world, except two kids named Lina Mayfleet and Doon Harrow. They find a secret tunnel and think they've found a way out of ember. Was ember an underground city? Did the passage they found lead to anything? You'll find out if you read the city of ember.