Here’s a nice visualization from Greg Charvat at MIT using a LED-equipped sensor to map out 2.4 GHz waves. The sensor detects the direction as well as magnitude, so you get two different colors. The 2.4 GHz frequency is used for Bluetooth, wireless sensors (especially ZigBee), Wi-Fi and almost every other gadget, if you’re in the US.
Its wavelength is a few centimeters. (In comparision, the wavelength of 60 Hz electromagnetic radiation is a few thousand MILES)
Now you can almost feel the positive and negative wavefronts thanks to this long exposure image, created by moving the sensing antenna around while the LED lights up.