I made a couple of crystal sets as a child. In 2015 I was given some suitable capacitors and a germanium diode so I made another one. There are no longer any AM stations in Germany so I was very pleased to tune into the English Language Service of Radio România Internațional on 5939 kHz from Statia Radio Galberni, 1165 km away. I wrote and told them and, to my delight, received a QSL card.
Details (nothng special) - antenna 12m. long, 1.80m. above ground, earthed to a radiator, antenna capacitor 330 pF, tuning capacitor 660pF, coil 70 turns of 0.3mm wire with taps, 1N34A germanium diode, piezo earphone.
Also some experiments with a diy piezo earphone, a diy high-impedance earphone and a diy cat's whisker with a lead galena crystal - a weak and capricious signal compared to the germanium diode.