1. Introduction  
2. The Optical and IR Datasets  
2.1. 2MASS Photometry for Bright Stars  
2.2. Deep VVV Survey Observations  
2.3. GLIMPSE and WISE Mid-IR Photometry  
2.4. Gaia Optical Photometry and Proper Motions  
2.5. DECAPS Optical Photometry  
3. Globular Cluster Physical Parameters  
3.1. Colour-Magnitude Diagrams  
3.2. Measurement of Cluster Reddening and Absorption  
3.3. Distance Determination  
3.4. Metallicity and Age Determination  
3.5. Radius Estimate  
3.6. Measurement of Total Luminosity  
3.7. Radial Velocities  
4. The RR Lyrae Puzzle  
5. Summary and Conclusions