Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Figure 23.13, the esophagus runs a mainly straight route through the mediastinum of the thorax. To enter the abdomen, the esophagus penetrates the diaphragm through an opening called the esophageal hiatus. Answer: thorax
Output:
The esophagus runs a mainly straight route through the mediastinum of what?