This is my particular chart of the well known inverted yield curve with the S&P500 (green line). The blue line reversal (marked by the circles) generally coincides with a big crash. Today it's near the green trend line (see white circle), which means that the reversal could happen soon.
Note
See my other 4 ideas of this "Crash Incoming?" serie.
Note
Update the chart and check where we are (at year 2000 level):
snapshot

Be careful, as always.
Chart Patterns

Disclaimer