Acts 1:12-13

The apostles choose Matthias to take the place of Judas

12 Then the apostles left the Mount of Olives. They returned to Jerusalem. This was a walk of about one kilometre. 13 When the apostles arrived back in Jerusalem, they went to their room. The room where they were staying was upstairs. Those apostles were Peter, John, James and Andrew; Philip and Thomas; Bartholomew and Matthew; also James the son of Alphaeus, Simon the Zealot, and Judas, the son of James.

1:12This was about half a mile.
1:13A Zealot was someone who fought for his nation against the Roman government.