The Eiffel tower is Paris’s most recognizable landmark, and is of key importance to @mlscience. So far, the Eiffel tower has been used in three separate calculations as a reference (one of which hasn’t been posted yet!). Really, we wouldn’t know what to do without it.
Melting the entire puddle iron structure of the Eiffel Tower (which means this excludes the stone foundations, paint, etc.) and compessing it into a big ball would give you this.
The sphere would have a volume of ~935,000 Liters and would weigh ~7,300,000 Kilograms.
Some more calculations regarding the Chemistry and Physics of the composition of the Eiffel Tower can be found here: http://www.thechalkface.net/resources/melting_the_eiffel_tower.pdf
It’s still pretty big.
(Sizes visualized with http://socialcompare.com/en/tools/compare-sizes)