1 - The world’s biggest bucket-wheel excavator

This machine is 984 feet long, the equivalent of about six Olympic-sized swimming pools in length. It weighs about 91 million pounds, the size of about 380 Blue Whales, which is the largest animal on the planet
Bagger 288 constructed by German company Krupp for Rheinbraun, is the world's largest land vehicle.
If you want to get the ore, dirt out, or move a mountain, it's what you need.
Bagger 288 removes 100,000 cubic yards per day.
The Biggest bucket-wheel excavator in the World Cost: $100 million
It Took 5 years to design and manufacture plus another 5 years to assemble
Maximum speed 1/3 mile per hour. 

2 - The biggest` moving man-made machine

Despite how huge and impressive the bagger 288 is, it just would not be fair unless it had a competitor in size. In Lichterfeld, Germany there appears to be another “biggest” moving man-made machine. This colossus of a machine is called the Overburden Conveyor Bridge F60.
Although it weighs less than the bagger 288 (only 11,000 tons instead of 45,500), its length is untouchable-502 meters, or 1,647 feet, (compare 300 meters, or 948 feet forthe bagger .) It is also 202 meters, or 663 feet wide. It was built in 1991 by VEB TAKRAF Lauchhammer. After only 13 months in operation, it was shut down for “energy-political” reasons.
To get an idea of how long this machine is in relative terms, if the Empire State Building fell over its length would fall about 200 feet shorter than that of the F60. If the Sears Tower fell over it would be less than 100 feet longer than the F60. Note this comparison includes the lightning rods and antennas of theEmpire State Building and the Sears Tower, which if it did not, the F60 would be longer in length than the height of both buildings. Also note that the Sears tower is said to be the tallest building in the world measured from ground to pinnacle point. Below is a picture comparison between the F60 and the Eiffel Tower.

3 - The worlds largest wheel loader.

The LeTourneau L-2350 monster wheel loader sports a 53 cubic yard bucket on its massive front arm. For these of you who still can’t picture that, try this: that’s enough space to hold a small fire-truck. LeTourneau builds these to work in some of thelargest mines in the world.
It’s powered by a 16-cylinder turbocharged diesel that delivers over 2300 HP to the wheels, which is enough to move it along at about 10-1/2 MPH. That doesn’t sound like much until you consider that it can do it while bench pressing 160,000 pounds 11′ in the air. It also comes in any color you’d like – as long as it’s construction yellow.

4 - The Caterpillar 994

The Cat 994 is a seriously big loader, alas, it's not the worlds biggest as already stated but at the time, it did employ the use of the worldslargest tires, until the Le Tourneau L-2350 came along and spoilt it !
The cat 994D has a V16 diesel engine that delivers 1500 hp, which is more than adequate for the work that it undertakes. It is equipped with a 4 exhaust stack system and each tailpipe is dedicated to the removal of exhaust from 4 cylinders, and this causes the engine to behave more like four engines operating in tandem.

5 - Giant truck set for sky-high task

A colossal 28-wheel truck that will help build a major telescope array in the Chilean Andes
The giant vehicle will heave antennas - each weighing 115 tonnes - up a mountainside to the site of the array, a plateau 5,000m above sea level.
The antenna transporter is 10m wide, 20m long and 6m high. It weighs 130 tonnes and has as much power as two Formula 1 engines.
The first of two vehicles has been put through its paces at the firm Scheuerle Fahrzeugfabrik near Stuttgart in Germany.
The vehicles will have to haul their heavy cargo safely from the 2,900m-high Alma base camp, where the antennas are assembled, to the array site, which lies at 5,000m - about half the cruising altitude of a 747.
Because of the low oxygen content of the air at 5,000m, vehicle operators will need to wear portable oxygen canisters. The backrests of the driver seats are shaped to allow the driver to wear his oxygen tank while driving.

6 - NASA Crawler-transporter

The crawler-transporter is a tracked vehicle used to transport the Saturn V rocket, the Saturn IB rocket during Skylab and Apollo-Soyuz Test Project, and now the Space Shuttle, from NASA'sVehicle Assembly Building to the Launch pad on a Mobile Launcher Platform. The crawler-transporter, built by the Marion Power Shovel Co. at a cost of $14 million, was once thelargest tracked vehicle in the world; it has since been surpassed by the German Bagger 288 excavator.

7 - Big Muskie

"Big Muskie" was once the World's Largest Earth Moving Machine. What remains today is a monstrous metal bucket, vaguely resembling a robot dog head. The bucket sits on a rise, overlooking the beautiful valley that it once mined and destroyed, which has been renamed "Re-Creation Land."
Built in 1969, Big Muskie could move 39 million pounds of earth and rock every hour, revealing rich coal seams 100-150 feet down in southeastern Ohio. BM could swing its boom 600 feet, creeping across the landscape on four giant shoes. The immense dragline machine was churning along at full production until 1991, when power demands and other factors convinced the owners to shut down.

8 - Heavy lift vessels

In the early morning of February 16, 2006, the semi-submersible vessel M.V. Kang Sheng Kou of COSCO Shipping, taking advantage of its advanced dynamic positioning system, accomplished a float-over positioning installation of the topside weighing more than
11000 tons in the PM3-CAA oilfield off Thailand Bay.