text: In the early 1900s, Werner Spalteholz developed a technique that allowed the clarification of large tissues, using Wintergrünöl (methyl salicylate) and benzyl benzoate. Over the next hundred years, various scientists introduced their own variations on Spalteholzs technique. Tuchin et al. introduced TOC in 1997, adding a new branch of tissue clearing that was hydrophilic instead of hydrophobic like Spalteholzs technique. In 2007, Dodt et al. developed a two step process, wherein tissues were first dehydrated with ethanol and hexane and subsequently made transparent by immersion in benzyl alcohol and benzyl benzoate (BABB), a technique they coupled with light sheet fluorescence microscopy. Hama et al. developed another hydrophilic approach, Scale, in 2011. The following year, Ertürk et al. developed a hydrophobic approach called 3DISCO, in which they pretreated tissue with tetrahydrofuran and dichloromethane before clearing it in dibenzyl ether. A year later, in 2013, Chung et al. developed CLARITY, the first approach to use hydrogel monomers to clear tissue.