Complex sentence: Within the Mediterranean, the Straits of Yucatán to the Gulf of Mexico connect with the Caribbean, and by the Panama Canal, built in the 20th century, it is connected to the Pacific.
Split into simpler sentences: Within the Mediterranean, the Straits of Yucatán to the Gulf of Mexico connect with the Caribbean. And through the Panama Canal, built in the 20th century, it is connected to the Pacific.