Complex sentence: He made another globe in 1520, which shows Antarctica, way before the officially known first discovery records, like the Piri Reis map, which was drawn in 1513, also shows Antarctica.
Split into simpler sentences: He made another globe in 1520, which some consider to show Antarctica, way before the officially known first discovery records. Like the Piri Reis map, which was drawn in 1513, some also say shows Antarctica.