RSA-250 has been factored.
This computation was performed with the Number Field Sieve algorithm,
using the open-source CADO-NFS software.
The total computation time was roughly 2700 core-years, using Intel Xeon Gold 6130 CPUs as a reference (2.1GHz):
RSA-250 sieving: 2450 physical core-years
RSA-250 matrix: 250 physical core-years
The computation involved tens of thousands of machines worldwide, and was completed in a few months.
News article. On the factoring challenges.