*Update, 19 December: View the 2019 Breakthrough of the Year!

*Update: Voting has closed. Check back on 19 December to see your winner, along with Science's choice for the 2019 Breakthrough of the Year.

On 19 December, the editors and news reporters of Science will announce their selection of the most significant scientific breakthrough of 2019. We invited you to choose from among the candidates and, with some 23,000 votes cast, the four below rose to the top. Now is your chance to decide which of them will be the People’s Choice for Breakthrough of the Year. Voting will close at 11:59 p.m. EST on 9 December. Check back after 2 p.m. EST on 19 December to see how your choice stacks up against ours.