Lottery players will have a shot at an estimated $820 million Mega Millions jackpot Tuesday night, less than a week after someone hit a Powerball prize that topped $1 billion.

The huge Mega Millions jackpot is the eighth-largest U.S. lottery prize and follows a $1.08 billion prize won by a player Wednesday in Los Angeles. California lottery officials haven’t announced a winner of that prize, which was the sixth-largest in U.S. history.

Jackpots in the two lottery games grow so large because the steep odds make winning so unlikely, allowing the grand prize to roll over again and again. The last time someone beat Mega Millions’ odds of 1 in 203.5 million and won a jackpot was April 18 — that’s 27 drawings without a big winner.

The game pays out many more smaller prizes, which start at $2. The overall odds of winning any prize is 1 in 24.

The $820 million prize for Tuesday night’s drawing is for a sole winner who chooses payment through an annuity, with one immediate payment and then 29 annual allotments. Jackpot winners nearly always take the cash option, which for Tuesday night’s drawing would be an estimated $422 million.

Mega Millions is played in 45 states, Washington, D.C., and the U.S. Virgin Islands.