What some could argue is the most infamous tank ever invented, the Panzerkampfwagen ausferon VI H otherwise known famously as the "Tiger". It was nicknamed by its German crews to scare its enemies and it stuck.
The Tiger sports an 88mm gun capable of defeating Allied Shermans and T-34's (The most manufctured and used allied tanks) at a range of up to 2 miles, its 100mm frontal armor is impervious to the Shermans low velocity 75mm cannon up until point blank as well. The Tiger first burst onto the World War 2 stage in Leningrad where it faced off against the famous T-34. The T-34 was no match for the Tiger at long ranges as its 76mm gun was not powerful enough much akin to the Sherman. It achieved remarkable success in Tunisia as well in 1943, the allied tanks had trouble fighting on the open desert plains, however there weren't enough to make a big difference. The Tiger also had plenty of teething problems during Leningrad as it actually entered service there as a prototype, it would often get stuck, and engine maintenance needed to be improved during the brutal winter. Some of these problems would be alleviated by 1944, but by then the Tiger was losing its advantage.
The infamous 88 Flak/Anti-tank gun, it was fitted to the Tiger (The 88 was organized into flak batterys, in certain cases during early Barbarossa, they would be rushed to the frontline to help eliminate KV-1 heavy tanks that were impervious to pretty much everything except it) 
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A great gif of 88's in action-
http://fat.gfycat.com/TartAgileFieldmouse.webmTigers were organized into separate heavy tank abteilungs (German for Battalion), so special was the Tiger that they were handed out piece meal in these battalions as divisional level assets. The Tiger was designed as a breakthrough tank, so where ever you saw a tiger, more than likely you were in the path of the German main effort. However, converse to that is the fact that you were actually pretty lucky or indeed unlucky to even see a tiger, in fact only about 1200 were made, contrast that with 8500 Panzers 4's, this fact makes Tiger panic even more interesting, a point I elaborate on towards the end of this post.
Much like the Panzer 4, the Tiger to went through alterations and versions, in Leningrad it was a prototype, learning from that the Germans adopted a few changes. The most major change was a lowered cupola, this change was made because the tigers cupola stood out a bit to much, the alter models had the hatch swing to the side instead to reduce profile, and also added a periscope for the commander to look through instead of the cupola windows. The Tiger tank was also one of many German tanks equipped with the Nahverteidigungswaffe (German for self defense system. This allowed the Tiger or other tanks to fire defensive smoke, or offensive mines about 5-10 meters in front of the tank. One last important change was the addition of "zimmerit" an anti magnetic mine coating, ironically none of Germanys enemy's used magnetic anti tank weaponry, the only thing they had to fear was the capture of those munitions from them.
Tiger 1 Early model with high cupola-
Late Tiger 1 model sporting Nahverteidigungswaffe close defense system and new cupola (Note how the hatch now swings to the side)-
Panzer 4 "H" (The side plates on the Panzer 4 H usually took the blame for making it look like a Tiger, those plates are designed to detonate shaped charge warheads fired from bazookas, or help stop AT rifle rounds)-
However the Tiger had its own fair share of problems both in its mechanical workings and of course the enemy's new weapons. For one it was simply over engineered, to build a Tiger it took a lot of hours and a lot of materials to make a Tiger, to the point where it was inefficient. German industry can be blamed in part for this because each part was made in a separate factory halfway across the country but this also helped out because allied bombing raids really couldn't stop tank production completely. Its tracks were hard to dismantle and replace, the transmission would fail and if a Tiger got stuck it took a lot of work to get it free, it was simply to heavy weighing in at 60 tons. As the war dragged on the tiger would meet its match with the new soviet tanks like the T-34-85 which was more than capable of dealing with it frontally at a comfortable range, and the IS-2 with its 122mm cannon that could crack it open like an easter egg two miles out. The Americans and British learned quickly as well, with the British adopting the Sherman "Fire fly" a Sherman that was retro fitted to fit the 17 pdr AT gun, which was more than capable of taking a tiger on a mile out. The Americans however had tank destroyers like the Hell cat, and up-gunned 76 Shermans that with special ammunition equipped were a match as well. These tanks were for the most part ready in 1943 and were fought with until the end of the war.
American "Hell cat" tank destroyer (Note the large 76mm gun, Hell cats usually carried a special round known as HVAP, which stands for high velocity armor piercing, this was a special round that could defeat tigers a mile out)-
Soviet T-34-85 (The T-34-85 is an up-gunned T-34 that mounts a modification of the soviet 85mm AA gun, most importantly the turret now can hold a commander and gunner independently. On the T-34-76 the commander acted as gunner and commander, now he can command the tank separately reducing work load)-
American 76mm Sherman (Note the increased turret space in the rear to accomodate the 76mm gun)-
Russian IS2 (Note the massive 122mm howitzer mounted as the main gun, contrary to popular belief the IS-2 wasn't designed necessarily to kill big cats like the panther and Tiger, it as well as the tiger was a breakthrough tank).-
British Sherman Firefly (Britain: Fixing American equipment to make it better from the Sherman to the Apache gunship) Note: The paint on the upper half of the barrel was an attempt to break up the silhouette of the gun so a firefly would be hard to tell from a normal 75 equipped Sherman. Also the radio is now mounted behind the turret in that bustle you see to accomodate the 17 pounder gun-
Although the Tiger was later outmatched and became obsolete its legacy lives on as one of the most feared armored vehicles in history. Often normal Panzer 4's would be mistakenly called Tigers, leading to Tiger "panic" which was literally a panic caused by someone identifying (or misidentyifying) that a Tiger was on the battlefield, which was caused by its terrifying reputation. I can't find another tank with that kind of infamy. From the sand swept dunes of Northern Africa to the streets of Berlin, the Tiger is the symbol of the panzer, and it is going no where any time soon.
Today there is only one surviving completely intact Tiger, Tiger 131 in Britain's Bovington tank museum, it was abandoned by its crew when a shell struck and damaged the turret traverse, the culprit was a British churchill, punching a bit above its weight. Tiger 131 can also be seen in the movie "Fury", it is the only movie where an actual working Tiger tank is shown moving around.
Tiger 131 (The only operational original Tiger tank in the world, note the damage below the gun where the 75mm shell hit and jammed the turret traverse)-
Fury Tiger 131 (As seen in Fury, note the tree limbs used as camouflage)-
Well first post, and many more to come, hopefully you learned something. Also don't be shy to ask me about posting on a topic you want to see!
World War 2 Tech! (#1 The "Tiger")