It's about as heavy as Christ the Redeemer (statue)
It's about half as heavy as a Tree (Sierra Redwood)
In other words, 0.000635 megatonnes is 0.490 times the weight of a Tree (Sierra Redwood), and the weight of a Tree (Sierra Redwood) is 2 times that amount.(a.k.a. Giant Sequoia, a.k.a. Sierran redwood, a.k.a. Wellingtonia, a.k.a. "Big Tree", Sequoiadendron giganteum)
The weight of wood in a Giant Sequoia is 0.0013 megatonnes. General Sherman, a specimen in Sequoia National Park in Visalia, California, is the largest tree in the world by volume, with an estimated weight of about 0.0019 megatonnes.
It's about four times as heavy as a House
In other words, 0.000635 megatonnes is 4.07 times the weight of a House, and the weight of a House is 0.2460 times that amount.(149 sq. m, single-level, unfurnished)
A 149 sq. m (1,600 sq. ft), single-story, unfurnished house (without extensive masonry) of the type commonly found in America would weigh approximately 0.000156 megatonnes, based on the weight of the included materials. In contrast, a yurt — a type of dwelling structure popular among nomadic peoples of East Asia — typically weighs less than 0.000000460 megatonnes.
It's about six times as heavy as a Blue Whale
In other words, 0.000635 megatonnes is 6.08 times the weight of a Blue Whale, and the weight of a Blue Whale is 0.1640 times that amount.(Balaenoptera musculus)
Blue whales weigh between 0.000105 megatonnes. The largest mammal to have ever lived, blue whales feed almost exclusively on krill — tiny invertebrates weighing about 0.000000000001000 megatonnes each.
It's about nine times as heavy as The Space Shuttle
In other words, 0.000635 megatonnes is 8.90 times the weight of The Space Shuttle, and the weight of The Space Shuttle is 0.110 times that amount.(for Endeavour, a.k.a. OV-105, a.k.a. Orbiter Vehicle-105) (empty weight, excluding main engines)
When empty, the space shuttle Endeavour weighs 0.0000710 megatonnes. The shuttle's spacious cargo bay carried the Chandra X-ray Observatory into orbit in 1999 — a payload that weighed 0.0000200 megatonnes.
It's about one-fifteenth as heavy as The Eiffel Tower
It's about one-twentieth as heavy as The Brooklyn Bridge
In other words, 0.000635 megatonnes is 0.04767 times the weight of The Brooklyn Bridge, and the weight of The Brooklyn Bridge is 20.980 times that amount.(a.k.a. New York and Brooklyn Bridge) (Manhattan and Brooklyn, New York City, New York) (total weight)
The total weight of the Brooklyn Bridge is approximately 0.01332 megatonnes. In a promotional event to prove the bridge's stability shortly after it opened, entertainer P. T. Barnum led a parade of 21 elephants across it in May of 1884.