If you're looking for anime similar to Boku no Tezuka Osamu, you might like these titles.
Christopher Columbus is a beautiful and entertaining series that recaptures the time when Columbus first rose to greatness, later to become one of history's greatest catalysts for his eventual discovery of America. Set in the 15th century, this series depicts his marvellous adventures and dramatic life throughout both his childhood, as well as adulthood, until his eventual death.
Hatta Yoichi is a civil engineer who travels to Japanese-ruled Taiwan in 1910 to build a complex irrigation system in the barren southwest. Hatta manages to overcome the initial doubts of local farmers, but a tragic tunnel accident eventually halts the project and shakes his confidence.
The fearsome warlord, the demonic king—Oda Nobunaga! Before he was trying to rule over Japan, he was a teenager who began his path to greatness with his younger brother and faithful followers. Through succession, betrayal, battles, and bonds between one another, the struggles these boys face promise a future where they can blossom into powerful men.