About 250 million sperm enter the vagina within 30 minutes. Here it shows the sperm entering up into the Vagina
About 60,000 sperm remain and must get through the cervix. The cervix is very hard to get through and it is mucus covered, but during ovulation it opens up a bit so it is easier for the sperm to get through.
About 3,000 sperm remain. They must make it from the uterus to the Fallopian Tubes.They are attacked by white blood cells during this.
Now only about 10-30 sperm are left alive and they still are getting attacked by the white blood cells in the Fallopian tubes.They are nurished so they can stay alive for hours and maybe even days.
Fertilization is when the sperm gets out of the Fallopian Tubes and meets the egg. A lot of stuff happens during this stage like capacitation and the chromosomes are delivered.
The zygote(sperm and egg) travel through the Fallopian tube towards the uterus. Then the protective wall breaks off and attaches to the wall of the uterus and starts to grow.