There is no New Testament city and apostle more closely associated with each other than Paul and Corinth. That association is well-earned, as I think you will see. When Paul came to Corinth in 51 AD he found a diverse city which made its living on the trade goods which passed through their isthmus. The north and south trade was between mainland Greece and the Peloponnese. The east and west trace was shipborne goods going to or coming from many points to the east and going to or coming from many points to the west (especially Italy & Sicily).
Corinth had a lively Jewish community and, as was his custom, Paul went first to the Jewish meeting place. He met Aquila and Priscilla, his wife, who, like Paul, were tent makers. So Paul lived and worked with them. Before Paul got to Corinth he had already heard that Timothy and Silas were delayed by trouble in Thessalonica and so he wrote 1 Thessalonians. Then when Timothy and Silas caught up with Paul in Corinth they gave him an update on Thessalonica and Paul wrote 2 Thessalonians. Paul stayed in Corinth for about 18 months before he left with Aquila and Priscilla to go to Ephesus (they may have traveled back through Thessalonica and Philippi).
After returning to his home base of Antioch (Syria) Paul began his third missionary journey by traveling through Galatia and Phrygia and on to Ephesus. In Ephesus Paul wrote his first letter to the Corinthians (1 Corinthians). He then made a short visit to Corinth (his 2nd: see 2 Corinthians 2:1, 12:14, & 13:1), traveling again through Philippi and Thessalonica, and then returns to Ephesus where he is put in prison. From prison Paul wrote a short letter to the Corinthians which we have as 2 Corinthians 6:14 – 7:1 (see 2 Corinthians 7:8-9).
When Paul is released from prison he traveled again to Philippi and Thessalonica. From there he wrote the rest of 2 Corinthians and then made his third and final trip to Corinth. This must have been a much better stay with the Corinthians than his 2nd visit because Paul was able to write his epistle to the Romans while he was in Corinth. This stay lasted for about three months (Acts 20:2).
Are there places that you have visited multiple times? What makes them special?