1886 HH&C safety.
The prototype bicycle, basically.
I'll post a resto thread when we get on to it, but given it sat in a barn for 50 years, one of my colleagues took it for a testride with no repair necessary.
I'm struggling to find 30" solid tyres, obvs
The cross frame replaced by the double triangle, the pneumatic tyre, the freewheel.
Millions of riders thinking about this revolutionary bicycle moved it from a toy to what it is today in about 2 years. Hive mind.