Brachiosaurus altithorax was described by Elmer Riggs in 1903 based on a specimen from the Late Jurassic (156 to 145 million years ago) of Colorado. However, the best skeletons are from the Tendaguru Hills of Tanzania, which, at the time the skeletons were collected, was known as German East Africa. Field work started in 1909 and continued until 1912. The dig was not a small affair. Almost $600,000 was raised to fund the dig. In 1909, 170 workers were employed, and their numbers swelled to 500 in 1911 and 1912. About 235 metric tons of fossil material was removed. No permits for further fieldwork have been issued for this area since the 1920's.
Thanks for description - Animal life club