World Metrology Day commemorates the signing of the meter Convention on 20May 1875. The Convention provides the basis for the establishment of a coherent international measurement system and supports scientific exploration and innovation, industrial production, international trade, quality of life improvement and environmental protection. The main purpose of the Convention is to ensure the international uniformity of measurements, which is as important today as it was in 1875. One of the major steps taken by the global metrology community was to review the International System of Units (SI) instead of artifacts; the system is now based on a number of fundamental physical constants. This year's motto for World Metrology Day is "Measurement for Global Trade." The slogan was chosen to inform about the importance of the role that measurements play in facilitating fair global trade by ensuring that products comply with technical standards and regulations and to satisfy customers. Have you ever wondered how many products are traded around the world? How much energy is exchanged across borders in the form of electricity or gas? You may not be aware of the exact amount of these values and think of simple measurements. You can rely on all of these measurements, because manufacturers, shipping regulators, and governments are doing a lot to ensure fair, accurate, and secure trade and transportation of goods. The International Organization for Legal Measurement (OIML) develops international recommendations for the purpose of coordinating the requirements of measuring devices. OIML also directs the OIML-CS certification system to facilitate international acceptance and global trade of measuring instruments under legal supervision. These international cognitive measurement systems provide the necessary confidence and reliability of measurements, provide an unparalleled basis for global trade in the present age, and help us face tomorrow's challenges