"And when he had opened the seventh seal, there was silence in heaven about the space of half an hour." - Revelation 8:1
Silence. Yes, silence in heaven. No rumblings, no horses, just silence. Silence as those on Earth are given a chance to pause and realise what has thus far taken place. One question which can be asked here is whether the pause is actually half an hour. Well, firstly it is about one half of an hour, so the figure is not definite but approximate. Secondly, since time does not transact in heaven, it is likely that this is an impression of the time - in other words, it literally felt like about half an hour of silence passed (and if we consider that this vision was given whole, it is possible that half an hour of time transpired on Earth at this period of the vision), as opposed to what the actual time was. Whatever the answer, this time represents a short period in which man is forced to consider and reflect on what has occured and what is likely to come.
After the silence, the seven angels standing before God are given seven trumpets. Another angel approaches the altar with a golden censer, is given some incense, and offers it along with the prayers of the saints upon the altar. He then takes the censer, fills it with fire from the altar, and casts it into the earth, from which resounds voices, thunder and lightning, and more shaking of the earth. The use of the preposition "into" is interesting here, as it adds another intricacy to this act - the fire from the altar should pass not only onto the earth, but also inside it. Perhaps this suggests that the fire from the altar descends even to hell itself, adding to the suffering of those damned. However, that is mere speculation on my part, and should not be taken as gospel.