Directions:

The Danish name for Copenhagen is København. Four key sites in Copenhagen are:
The Bymuseum (City Museum), where a sample of hafnium oxide is displayed (hafnium is named after the Latin name for Copenhagen), Vesterbrogade 59, N55 40.33 E12 33.20.
The Niels Bohr Institute, where hafnium was discovered, Blegdamsvej 17, N55 41.80 E12 34.30.
Ørsted's Laboratory, the site of the discovery of aluminum, Studiostræde 6 - N55 40.75 E12 34.24.
The Geological Museum, with important samples of hafnium and aluminum minerals, Voldgade 5-7 - N55 41.24 E12 34.64.