Conversation so far:
What is henna in regards to Arab Weddings?
A woman draws henna or mehndi, a temporary form of skin decoration using henna, on the bride and guests' skin — usually the palms and feet
Is there any special meaning to the designs of henna made on the bride and guests' skin?
The designs are very intricate. Often hidden within the mehndi pattern, the name or initials of the groom are applied.
How far back does the tradition of henna night go?
This goes back into old Palestine.
Is the tradition of putting henna on the hands of the bride and groom only performed in arab countries?
A henna party is a tradition held before a wedding in many Middle Eastern and North African cultures.
Are there any other uses for henna besides putting it on the hand?
Women usually apply mehndi designs to their hands and feet, though some, including cancer patients and women with alopecia occasionally decorate their scalps
Are the couple allowed to see eachother on the henna night party?
Yes, the groom will enter where the bride is, they will both get their henna done, and the groom will then offer the bride her mahr.

Question: What is a mahr?
Self-contained rewrite: What is the mahr that the groom gives to the bride?