Lumbini is the birthplace of gautam buddha. Buddha was born here aroud 5000 years ago. Tilaurakot is the palace of buddha, wheile he was prince. History if buddism and flat land of terai are things to see in this part of Nepal.
Lumbini is famous among Buddhist tourist as well as luxury travelers coming to nepal. If you have interest to do medation lumbini is a best place to do meditation and yoga.