According to the Guinness Book of World Records, the heaviest thing to ever be weighed as of 2015 was the Revolving Service Structure of launch pad 39B at the Kennedy Space Center in Florida. It weighed 2423 tonnes, or 5,342,000 pounds, and required 21 jacking points to lift.
However, the heaviest object ever to have been created by man is the Troll A Platform, which is an offshore natural gas drilling platform stationed off the coast of Norway. It is estimated to weigh 1.2 million tons and is 1,548 feet tall. It holds the title for being the heaviest and tallest thing humans have ever transported, and required the use of 10 tugboats to drag it to its location.