A new study has found a terrible bottleneck in human ancestors about 900k years ago. There were as few as 1000 individuals left ... if this is verified further there was a time when we almost didn't make it. 

https://www.science.org/doi/pdf/10.1126/science.adj9484?casa_token=VS5dMv1ze_YAAAAA:v_FMiEjYJUA2-lPfVrsCOG4Lmaz039L-TwYp2grgDR3NQegiogx55LWUx2hkI9yF_laj_HLllS7S

https://cdn.masto.host/sauropodswin/media_attachments/files/111/020/256/447/368/899/original/c26b2f335a286eb6.png