3000 Leagues in Search of Mother (母をたずねて三千里, Haha o Tazunete Sanzenri) is a Japanese animated television series directed by Isao Takahata that aired in 1976. It is loosely based on a small part of the Italian novel Heart (Cuore) created by Edmondo De Amicis, i.e., a monthly tale (racconto mensile) From the Apennines to the Andes (Dagli Appennini alle Ande), widely expanded into a 52-episode epic.

The series was broadcast on World Masterpiece Theater (Calpis Children's Theater back then), an animation staple that showcased each year an animated version of a different classic book or story. It was originally titled From the Apennines to the Andes. Nippon Animation, producers of World Masterpiece Theater, adapted Cuore into a second anime television series in 1981, although this second series was not part of the WMT.

The series was dubbed into several languages and became an instant success in some countries, such as Portugal, Brazil, Peru, Spain, Venezuela, Colombia, Germany, Chile, the Philippines, Malaysia, Turkey, Iran, the Arab world, and Israel. In some European and in Latin American countries the series is simply known as Marco. In Arabic the series was a huge success; it was called Wada'an Marco (وداعاً ماركو), meaning Goodbye Marco. In Hebrew, the series was called HaLev (הלב), meaning The Heart and was popular in Israel especially during the 1990s).