Magnetotelluric
Maxwell equations can be printed in a T-shirt, instead of in a thesis. Tensor impedance matrix can be written in the wall of a bedroom, instead of in a dissertation. Although for some people, usually bachelor students, those two thing are worse than have a headache.
At the beginning, it was very hard to understand Maxwell and Helmholtz equations. It was also not easy to explain tilt angle in VLF and impedance tensor in MT. Year after year of consistency, finally I found out that it is just about electromagnetic wave, something in our daily life.
The sun generates solar wind, which is a source of electromagnetic waves in small frequency (i.e. smaller than 1 Hz). Thunder storms generate electromagnetic waves in high frequency (i.e. higher than 1 Hz). Power lines generate electromagnetic waves in frequency around 50 Hz and its harmonics.
Electric and magnetic waves travel together around the world. They should be unseparatable to be called electromagnetic waves. When the EM waves have to travel through some places (medium), they adapt with the character of the places (e.g. conductivity).