sentence1: For sailors, the lighthouse of Alexandria ensured a safe return to the Great Harbor; for architects, it was the tallest building on Earth; and for scientists, it was the mysterious mirror that fascinated them most: its reflection could be seen more than 50 km (35 miles) off-shore. For all these reasons, the lighthouse was considered one of the Seven Wonders of the world.
sentence2: The lighthouse of Alexandria was one of the seven wonders of the world.