The Temple of Human Passions (French: Temple des passions humaines; Dutch: Tempel van de menselijke driften), also known as Pavillon Horta-Lambeaux, is a neoclassical pavilion in the form of a Greek temple that was built by Victor Horta in 1896 in the Cinquantenaire Park of Brussels. Although classical in appearance, the building shows the first steps of the young Victor Horta towards Art Nouveau. It was designed to serve as a permanent showcase for a large marble relief "Human Passions" by Jef Lambeaux. Since its completion the building has remained almost permanently closed.
In 1889 Victor Horta was commissioned for 100 000 francs to design a pavilion to house Jef Lambeaux's sculpture "The Human Passions" on the recommendation of his teacher Alphonse Balat, King Leopold II's favourite architect. The small temple of classic look already announced the Art Nouveau manner associated with the architect. Although loyal to the formal vocabulary of classical architecture, Horta already managed to incorporate all elements of the new style. At first sight, the building looks like a classic temple. However, there is not a single straight line in the building. Every classic detail is revisited and reinterpreted. Horta succeeded in designing an almost "organic" interpretation of the classical temple, without completely abolishing any reference to an historical style. Slightly bent like the foot of a tree, the walls seem to have sprung organically.
The small neo-classical pavilion was originally planned for the 1897 Brussels International Exposition. Although completed in time for the fair, the collaboration between the architect and the artist soon led to an irreconcilable disagreement delaying its official opening until 1899. At first, Horta designed the pavilion's facade to be open, serving as a shelter on rainy days — without the wall and bronze doors behind the colonnade — so that the relief would always be visible for passers-by. But Lambeaux, against the will of Horta, wanted a gallery wall behind the columns. The dispute remain unsolved for years: on the day of the inauguration on 1 October 1899, the unfinished temple stood open with the relief visible from the surrounding park. Under pressure of the public opinion and the authorities Horta had to alter his plans and close the temple with a wooden barricade. It was left unfinished only three days after inauguration. Lambeaux never knew the temple as it currently stands. Shortly after Lambeaux's death, Horta acceded to his wishes by building the wall that would permanently hide the bas-relief with a closed front to enhance the natural light coming through the glass roof.
The Horta pavilion houses the monumental achievement of the sculptor Jef Lambeaux (1852–1908): the relief "Human Passions". Commissioned in 1890 by King Leopold II for 136 000 francs, the 12 by 8 metres (39 × 26 ft) work was centered around the theme of the happiness and the sins of mankind dominated by death. It also depicted the "negative" passions of mankind such as war, rape and suicide.
Since 2002, the temple is open one hour per day, except on Mondays. In recent years this was not due to the prudishness of the public, but out of fear for vandalism.