▁Tell , ▁Christopher ▁Columb us , ▁Black be ard , ▁Captain ▁Cook , ▁Leon ardo ▁da ▁V inci , ▁Robin ▁H ood , ▁George ▁Washington , ▁Att ila ▁the ▁Hun , ▁Hern ando ▁Cor te z ▁and ▁Daniel ▁Bo one . ▁ ▁Like ▁early ▁episodes ▁of ▁Doctor ▁Who , ▁which ▁premier ed ▁in ▁the ▁UK ▁more ▁than ▁a ▁de cade ▁later , ▁most ▁episodes ▁were ▁mel od ram atic ▁history ▁less ons ▁for ▁children . ▁No ▁serious ▁effort ▁was ▁made ▁to ▁explain ▁how ▁the ▁time ▁machine ▁worked , ▁and ▁time ▁travel ▁con und ra ▁( such ▁as ▁the ▁grand father ▁par ado x ) ▁were ▁like wise ▁gl oss ed ▁over . ▁ ▁Each ▁week ▁after ▁the ▁last ▁commercial , ▁the ▁announ cer ▁would ▁int one : ▁" Be ▁sure ▁to ▁be ▁standing ▁by ▁when ▁we ▁again ▁transmit ▁you ▁to ▁the ▁remote ▁location ▁on ▁planet ▁Earth ▁where ▁Captain ▁Z - Ro ▁and ▁his ▁associ ates ▁will ▁conduct ▁another ▁experiment ▁in ▁time ▁and ▁space ." ▁ ▁Format ▁and ▁effects ▁The ▁special ▁effect ▁to ▁represent ▁time ▁travel ▁was ▁a ▁simple ▁dissol ve ▁shot , ▁set ▁among ▁flash ing ▁lights , ▁bl inking ▁oscill os cop es ▁and ▁numerous ▁le vers ▁and ▁kn obs . ▁ ▁Early ▁episodes ▁( 1 9 5 1 - 1 9 5 3 ) ▁were ▁k ines cope ▁record ings ▁( film ▁shot ▁off ▁a ▁TV ▁monitor ). ▁Later ▁shows ▁for ▁synd ic ation ▁( 1 9 5 5 - 1 9 5 6 ) ▁were ▁shot ▁directly ▁to ▁ 1