Which is a complex sentence?

 - We discussed a variety of topics, including Mexican art, Canadian politics, and Japanese food.
 - Although she left her house early, Nellie barely made it to the train station in time.
The second sentence is the complex sentence. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction although.
Although she left her house early, Nellie barely made it to the train station in time.