Where i can check a log about the last reboot time of my freebsd box

[Carlos Alarcón]

Hi, im having troubles with a freebsd box, suddenly this fbox reboots many
times on a day, every hour at least, :(, i dont know what could be
happening, this fbox was working great, i'd like to know if a log on the
system could helpme to check if a program or process is making some bad
things..
With this box i share internet to many clients.. am worried :(.
thanks in advance.

Carlos Alarcón