Timeline of three longest spans

This is the timeline of the three longest man-made spans in the world, all categories, that at least have the strength to carry some persons. It can be the span of any type of bridge, aerial tramway, power line, structural ceiling or dome etc.

In this timeline, only spans that were still standing in a particular year are considered for that year. This is perhaps more fair than a timeline of the records of all time, because the old figures might be incorrect. At the points when the old spans fall, new spans with more certain figures are allowed to appear in the timeline. This is a top-three list of existing longest spans per day.

When several structures of the same length exist, the oldest is counted as the longest.

Some more rules for this timeline follow as: Only the length of the horizontal projection of the span, that is, the distance that can be measured on a map, counts. When the two supports have different heights above the sea level, the distance between them is longer than the horizontal projection of the distance, but this longer distance isn't counted. This is because it is more difficult to build a 100-metre (330 ft) horizontal span than a 100 m span that is tilted perhaps 45 degrees, as if it was the support for an escalator. The stress in the material is higher for the horizontal span, creating higher engineering difficulty, so only the length of the span perpendicular to the force of gravity is counted. For many structures in the timeline, it is not known if the stated length is the desired horizontal projected length, or the direct "laser beam" length.

Spanning structures in water are included only if they would still be standing if the water were removed.

The longest 5,376 m (17,638 ft) Ameralik Span and others have pylons that are not completely man-made. The lines are attached to small man-made pylons that in turn stand on the mountain, which forms the rest of the height of the pylons required for a span of that length. If the present man-made pylons were placed in a flat area, there would be no span, because the lines would touch the ground. It could be argued that this span should not appear in the timeline because the pylons are not completely man-made. However, as the focus of the engineering design task here is not to make something that is tall, but to make something that is long, it is concluded that this type of span is enough man-made to be in this timeline.

...
Wikipedia