The medium with the highest speed of sound is typically a solid, particularly metals. In general, sound travels faster in denser materials, which is why it propagates more quickly in solids compared to liquids and gases.

For example, in typical conditions:

• Sound travels through air at a speed of approximately 343 meters per second (1235 kilometers per hour or 767 miles per hour).
• Sound travels through water at a speed of around 1,480 meters per second (5328 kilometers per hour or 3310 miles per hour).
• In contrast, sound can travel through metals at speeds ranging from several thousand to over 10,000 meters per second (several kilometers per second).

So, sound travels fastest in solid materials, making metals the medium with the highest speed of sound under normal conditions. The exact speed of sound in a specific metal can vary depending on factors like its density and temperature.