“[…] As soon as Daniel knew that the decree had been signed, he went to his house, which had the windows of his roof chamber open toward Jerusalem. And three times a day he got down on his knees and prayed […].”
~Daniel 6:10

Daniel had not seen Jerusalem since his childhood, and would probably not see it again in his lifetime.
Still, the values his parents instilled in him at a young age guided him until he was elderly. (Prov. 22:6)
He never lost view of what the most important thing in life is: one’s personal praise toward God. (Ps. 145:2)
Jerusalem was supposed to be the hub for pure worship of Jehovah, and Daniel regularly reminded himself that was where he came from. (2 Chron. 6:20,21)
He realized God’s purpose endures forever and it had not been lost with the exile of the Jewish people. (Jos. 23:14; Isa. 40:8; 1 Pet. 1:25)
Daniel set an excellent example of being spiritually constant despite difficult, changing circumstances, conscientious of the most important things. (Phil. 1:10)