Coin collecting is a popular hobby, and some rare coins can fetch a high price on the market. Here are some of the world's rarest coins:

1933 Double Eagle: This is the rarest and most valuable coin in the world. Only 13 of these coins were ever released, and most were subsequently melted down. In 2002, one was sold for over $7 million.

1794 Flowing Hair Dollar: The first silver dollar ever minted in the United States, only 140 of these coins are believed to exist. In 2013, one sold at auction for over $10 million.

1894-S Barber Dime: Only nine of these dimes were ever minted, and only one is known to still exist. In 2007, it sold for over $1.9 million.

1804 Silver Dollar: Only 15 of these coins were ever minted, and they are considered some of the most valuable coins in the world. In 2017, one sold for over $3.8 million.

1913 Liberty Head Nickel: Only five of these coins were ever minted, and they are considered some of the rarest coins in the world. In 2018, one sold for over $4.5 million.

Collecting rare coins can be a thrilling hobby, but it is important to do your research and be cautious of counterfeits. Experts recommend buying from reputable dealers and investing in a grading service to ensure the authenticity and condition of the coins.