world-mysteries.com

yrBM TIL nobody knows who built the Taj Mahal. The names of the architects, masons, and designers that have come down to us have all proved to be latter-day inventions, and there is no evidence to indicate who the real creators were.
ErrV TIL an iron pillar in Delhi(made of 98% wrought iron) has stood for at least 1600 years without rusting or corroding.