For assignment I have to take SRTM raster data and created DEM map. I also have to change the projection. I was able to bring SRTM tiff data into ArcMap 10.3. I try reprojecting by going to Project Raster toolbox (Data Management Tools>Projections and Transformations>Raster>Project). I try dragging the data in "Input Dataset or Feature Class" but than recieve the following message: One or more dropped items were invalid and will not be added to the control. It won't list the data in the drop down list.