Prior to Christ Jesus' ascension to heaven 40 days after His resurrection, when a person died, their immaterial side (their soul and spirit) went to a place in the heart of the earth known as Hades or Sheol.
At that time, there were two areas. One area was where the righteous dead were held captive awaiting Christ Jesus' victory on the cross of Calvary as the perfect Lamb of God that takes away the sin of the world. The other area was (and still is) the area of the un-righteous dead.
At that time, there was a gulf between the two areas (one could not travel from one area to the other.) They could see each other, however.1
When Christ Jesus ascended to heaven 40 days after His resurrection, He took those held captive in the area of the righteous dead (Abraham's Bosom or Paradise) to heaven with Him; Paradise is now in heaven.2
Since that time, those held captive in Hades (the un-righteous dead) are no longer able to see the righteous dead (those who are now in heaven.)
1 (Luke 16:19-31)
2 (Ephesians 4:8;
2 Corinthians 12:2-4)