The first recorded Scout rally attended by both Boy Scouts and Girl Scouts, was at Scotstoun Stadium in Glasgow, in June 1909. But since then it has deliberately been described as a gathering or event, in order that the rally held at Crystal Palace in London three months later could be deemed the 'first Scout rally'. Many myths surround this Crystal Palace rally - it is not true that Girl Scouts were there unexpectedly. It is not true that Robert Baden-Powell wasn't aware of the existence of Girl Scouts. It isn't true that there were only a small number of Girl Scouts there - there were several separate groups of Girl Scouts, and also several individual Girl Scouts there. Some estimates say several hundred Girl Scouts attended. Certainly, by the end of 1909 there were 6000 Girl Scouts registered at Scout Headquarters (that they knew of), not to mention those who were not registered, or those whose application forms didn't make it clear whether they were girls or boys. It isn't true that there weren't any groups for girls - organisations including Girls' Brigade and Band of Hope were already in existence - so the girls didn't need to ask for 'something for the girls' - they had something, even if what they had wasn't quite what they wanted.
From Guiding's early days, rallies were a regular thing. Sometimes at Division level, sometimes at County level. They tended to involve gathering at a large park, or country estate. There might be inter-unit competitions, demonstrations, performances, and games, and the event often concluded with a formal march-past, with a dignitary or senor Guiding figure taking the salute. Units would walk or travel by train, bus or charabanc to a central location, often taking packed food with them. Rallies tended to mainly be events for Guides, with the equivalent event for Brownies being called Brownie Revels. Since that time, joint events for Rainbows have been held, sometimes referred to as Rainbow Riots.