Stripping away the apocalyptic imagery:
7 seals (Rev.6:1-14,8:1-5)
. Judgments of war/conflict/strife
.Economic hardship/famine
.Domination/destruction/deprivation/death
7 Trumpets: Rev.8:6-9,21,11:15-19
.Judgment of natural disasters
.Untimely deaths
.Unnatural contamination of water and environment
.Mass murders
7 Bowls of Gods Wrath (Revelation 16:1 21)
.Sickness/diseases/festering sores
.Contamination of natural ecosystem like oceans,rivers, and streams
.Scorching of humanity by the Sun
.Plagues
.Humanity cursing God and refusing to repent
.Natural disasters like earthquakes, and hailstorms
Significance of "sevens". 7 is a number of completion/perfection. The tribulation will last as long as it needs to last to suit God's purposes.
Conclusion: the Tribulation has been ongoing during the entire Church age and will continue, getting progressively worse, until Jesus returns.
