Dams and cataracts.
The Nile river is the longest river in the world, though its hard to say if its "navigable" or not given that at two points in the river it has large rapids and waterfalls.
Missouri at 2,540 miles
The state of Mississippi is the 32nd largest of the US states. (The Mississippi River is the longest single river in the US. The Jefferson-Missouri-Lower Mississippi combination is the longest combined flowing river, 4th longest in the world, although much of the western Missouri is not navigable.)
At 1,013km (629 miles) the Loire is France's longest river, though not all of it is navigable. Its main tributary is the 396-km (246-mile) Cher. The Loire rises in the Cévennes in south-eastern France and flows through Orléans, Tours, Angers and Nantes until it reaches the Bay of Biscay.
The Darling River has the longest river catchment, as it is fed by numerous large rivers in its headwaters. However, it is not the longest river. The longest actual river is the Murray River.
The longest conclave was 105 days and took place in 1799 however went on in to 1800
however hard you kick it
There are no working trams in Scotland. However, the longest train journey is from Edinburgh to Inverness (via Stirling)
The longest curtain rods out there are 120", however custom curtain rods can be made longer if neccessary.
The River Severn is the longest waterway in Britain by about five miles. However, part of it is within Wales so the longest waterway wholly within England is the River Thames.
Counting all of Russia, Norway has the second longest coastline of any European nation. However, disregarding Russia, then Greece has the second longest coastline.
There are no (Kept) records for this category. However the PCP (PreCharged Pneumatic) Class of air rifles will have the longest range.