Complex sentence: In the summer of 2002, a double eagle dated 1933 was auctioned off for over $7 million US, which shattered the old record of just over $4 million paid at a public auction for a coin.
Split into simpler sentences: In the summer of 2002, a double eagle dated 1933 was auctioned off for over $7 million US. This shattered the old record of just over $4 million paid at a public auction for a coin.